You seem to think that discretionary income and emergency funds are widely different, you emergency funds comes from your discretionary income the same way your investment comes from it as well, discretionary income isn't necessarily meant only for investment, the amount of discretionary income you decide to use to invest depends on how aggressively you want to buy bitcoin and after investing you can always put what's left from your discretionary income into your emergency funds, this is because an emergency fund isn't a part of your daily, weekly or monthly necessity, so you can only save for emergencies after you have taken care of what's necessary and once you have taken care of what's necessary you are left with your discretionary income which you then split between investing in bitcoin and saving up for emergency. Also, you don't save up for emergency indefinitely, after saving up for a few months worth of emergency funds you can decide to put the rest of your discretionary income into building up your portfolio and you can rise from investing on a medium level to becoming an aggressive investor, you should know that buying aggressively doesn't necessarily depend on how big your investment is compared to what others are investing but how big your investment is compared to your total discretionary income so the more of your discretionary income you invest in bitcoin the more aggressively you are buying bitcoin.
Your comment about not saving for an indefinite period for emergency funds basically implies that emergency funds should be limited in amount, which is correct. However, there should be a clear goal for emergency funds. So that it is understood that saving for how many months of expenses will be enough for you. If the emergency fund runs out in an emergency, you can get stressed. There are many who are suffer from complacency by keeping a small amount of emergency funds, which is dangerous. On the other hand, there are many new investors who do not consider the need for an emergency fund. This is understood only when the fund runs out and you are really at risk. You need to have a cash flow plan for at least 3 to 6 months or 12 to 18 months. Or you can set a threshold for an emergency fund by determining your safety margin. However, I believe that being financially secure is essential if we want to succeed in our investments.
Part of the reason that we may tend to not want to keep various back up funds in cash for more than 3 to 6 months of our expenses is because cash tends to lose its value, and the more of it you are holding the more your value is being eroded away.. yet when you are brand new to investing, and you don't have much net worth or many assets or much cash, you likely have to build at least a minimum buffer from your investments in cash.
The longer that you are investing, the more likely you are building up more and more wealth and you are not necessarily wanting to keep very much of it in cash, yet if you don't have any other income, then you might keep more in cash, versus if you have income, then you don't need to keep as much in cash, and even various investments that you have may well serve as back ups to your cash, so you might have an order in which you might cash out of various investments some are more liquid than others and some are more volatile than others, and if you have been investing for 10-15 years or longer, you might have assets besides just bitcoin and cash, perhaps. It is not necessary to do so, yet I believe that once your bitcoin is getting close to 1 year of your expenses or even more than 1 year of your expenses, you have the option to consider the extent to which you might want to have value in other assets such as stocks, bonds, property, commodities, cash/cash equivalents.
Some people come to bitcoin and they already have other investments and they will be left with a choice whether to continue to contribute to their other investment while adding bitcoin or to focus on bitcoin alone or maybe even to cash out of some of their other investments and put some or all of that value into bitcoin. Those are not bad problems to have, yet part of the choice will have to do with assessing the other investments in terms of their liquidiy, their volatility and their likelihood to increase or decrease in value with the passage of time. Presumptively we are mostly focusing on bitcoin based on our thougts/speculation that it is going to hold its value and/or potentially appreciate in value more than other assets and/or currencies.
This was indeed an educative response as I have grabbed some solid points which you have elaborated on, and i can i say that i completely agree with the way you laid out those points. Cash does indeed serve its own purpose, especially when folks are still relatively in their early stages of building their financial base. When folks have that initial buffer of around 3-6 months' worth of expenses, it gives them that financial security, peace of mind and also literally protect them from tapping into their investment, should incase financial needs that requires their immediate attention arises in subsequent time. But just as you have rightly stated, that doesn't in any way mean that cash or fiat is an ideal way to store one's value for the long term because inflation can easily and slowly make make the value of your wealth fade away overtime.
The best part about investing in Bitcoin is that, the more one continues investing and growing their Bitcoin portfolio, the lesser they rely on Fiat or cash as a safety net. At this point, rather than cash, folks will now rely more of their other income streams, their diversified investment and even the growth of one's Bitcoin position could sometimes potentially serve as back up layer, which potentially reduces the need to leave a huge some of cash just lying around. I also saw lots of sense in your perspective and point about diversifying to other asset classes when folks notice that their Bitcoin holding has actually reached a point of covering a year or more of their living expenses, and this isn't because Bitcoin isn't reliable or a bad place for your funds to be but simply because it also makes sense to allocate into other other asset classes, and diversifying to other assets helps to balance liquidity, time horizon and even volatility.
You are also right about the fact that different people who get started in Bitcoin investment do so from different starting points. An individual who already have an existing stock or other investments will definitely have different decisions to weigh compared to someone who is still very new to investment and hoping to have Bitcoin as their first serious asset. Either ways, the key lies in what you said, which is the individual's ability to weigh volatility, liquidity and the long term growth and potentials of the asset. Unlike other traditional assets, Bitcoin has displayed and shown its uniqueness because of its asymmetric upside, but context is really important and matters a lot when it comes to integrating it with everything else.