Both are very vital when comes to bitcoin investment (discretionary income and emergency funds ) . You need discretionary income to keep buying , because is like a left over which means that is money they you can put into anything (like your savings or investments) .
While emergency funds, certain amounts of money set aside to play the role of taken care of emergency expenses. And some time , some expenses come without any warning . So emergency funds always there to take care of such expenses.
Yeah you’re right, both are really important because if you do not have an emergency fund, life will eventually corner you into selling your Bitcoin at a bad time. People throw everything into BTC, then when an unexpected expense comes up, they panic sell and end up regretting it later. Having that backup cash on the side just makes the whole journey less stressful.
And with discretionary income, that is honestly what keeps your buying consistent without messing with your daily needs. Since it is extra money, you do not feel the pressure when the market dips, you just keep stacking little by little. One takes care of the present, the other builds the future, that balance is what makes the whole plan work.