I totally agree with you, just imagine an investors doesn't have any discretionary income and the investor start to invest without an emergency fund attached to it, such investor will find it difficult to wait for longer term.
And mostly the newbies that is it coming up with their investment that doesn't have discretionary income, will not be that patient enough to wait for a long term for like 5-20yesrs but with time i know that they will eventually invest in long term because this life one will actually start from somewhere as you can afford believe that you will surely make a changes with respect to time.
To invest is to have income to do so - if you will worry about each part of the investment you put out when you can, it will not end up well.
We just need to invest what we can, when we can - and keep doing it steadily.
That's just the point buddy, just
invest what you can afford to lose from your weekly or monthly income then you are good to go, why most Investors are struggling to keep to their investment or keeps on buying regularly is because they are overdoing it more than they can afford, but if it's done with am amount they can do away with and in their own pace, nothing is stopping them from not buying and holding firmly for a very long time.
Using the word investing what you can afford to lose is what set's me off balance whenever i see that kind of statement, why not just say invest within your discretionary income rather than saying invest in what you can afford to lose, this statement is a make belief that tries to portrays bitcoin as some sort of gambling that you shouldn't invest what you cannot afford to lose. Bitcoin has had a steady growth right from inception, it hasn't shown any serious investor that they will at any point lose their investment, by serious investor I mean a long time holder, so the need for such kind of remark doesn't arise.
You are getting the wrong understanding and misinterpretation of that word "use the amount of money that you can afford to lose" it still means your discretionary income, because you can do whatever you like with your discretionary income and it wouldn't affect your monthly needs and expenses. Some people use their discretionary income to gamble, club, party, drink and all sort of things that wouldn't add any value to their life because it's the money that they can afford to lose.
This is why you are advised to use such funds to invest in bitcoin doesn't mean that you see bitcoin as an inferior asset. Also bitcoin investment is not guaranteed to be profitable in future even though we know that the odd is high of the price moving uptrend in future than downtrend, so that you can think carefully and invest wisely without using all your life savings to invest in bitcoin. Incase bitcoin didn't perform well in future as you expected, you will not be disappointed and hopeless. I like the word use what you can afford to lose to invest because it sends to lot of messages and caution to you on the amount to be invested into bitcoin.