If an investor is strictly investing in bitcoin with his discretionary income, he is free to invest in bitcoin with all his discretionary income if he chooses to do that,
No, I don't think it's a good idea to invest all of your discretionary income because their are so many things we spend money on that are not part of our basic needs, but are very important, so like 60% is ok, anything more than that might put you into a difficult state in sorting out those expense that is not part of our basic needs.
There's nothing wrong with investing all of your discretionary income, as the most important thing is that we've met all our basic needs, and we can still postpone any desires or spending.
Personally, I'm like this because as long as I can afford to invest, I'll do so for the future, even if it sometimes requires aggressive action.
Any financial crisis that happens after you have paid for your monthly expenses should be treated as an emergency because you don't plan for it,
No I disagree with this statement here, when we are talking of emergencies, we are talking about real life emergency situation that threatens your holdings, not minor expenses that can be sorted out with our reserves funds or a fraction of our discretionary income, that's why it's not good to invest with all your discretionary income so that you wouldn't have to act in such a manner at a point.
Before deciding to invest, we must first stabilize our finances, saving some for emergencies, but after that, we must strive to ensure our investments remain undisturbed.
Many things happen beyond our control, so we must work harder to earn more money each month to cover them all. I'm confident that if we're consistent with our high aspirations, we can do it.