It would have been problematic if you wanted to invest in bitcoin aggressively with the money you are supposed to use to solve your expenses, but since you want to use all your discretionary income to invest in bitcoin, I don't have any problem with your decision, and it is even good for you to use all your discretionary income to frontload your bitcoin investment since you are no coiner or low coiner rather than using it to live a lavish lifestyle that will expose you to sell your bitcoin investment too early.
No, I don't think that using your discretionary income to live a lavish lifestyle will compel you to sell too early, what actually makes you to sell prematurely is when you fall to put your emergency and reserve funds in place, and then emergency struck, that's what makes you sell too early even when it's not your intention.
I know that discretionary income is the leftover money after you have paid for monthly expenses, and you are allowed to use your discretionary income the way it pleases you. I still believe using your discretionary income to live a lavish lifestyle will drive you to sell your bitcoin too early. For example, you can go to a club and mistakenly spend way more than your discretionary income, and if you don't have any other money elsewhere that you could use to complete the money in your hand and pay for the extra expenses you incur in a club in the process of living a lavish lifestyle with your discretionary income, it can drive you to sell your bitcoin too early to pay for your bill in a club so that you could go home and rest.