Honestly speaking I don’t think there is anything wrong if an investor choose to invest all his discretionary income into bitcoin, considering that you have taken care of your expenses and you’ve an emergency and reserved funds, if I choose to invest all my discretionary income into bitcoin, instead of using it to extravagance lifestyle of buying cloths and during drinks and cigarettes and clubbing, at this point of my accumulation stage I think there is no need for such lifestyle.
I would prefer using my discretionary income to buy more Bitcoin and be more aggressive instead of using my discretionary income for some unreasonable and unrealistic activities.
Using all of your discretionary income to invest in Bitcoin might be problematic for you in the future because their are some things we buy that is not part of our basic needs but are very important for our very own existence, something like airtime or data subscription, they may not be part of our basic needs but it's very important that you have them in order to browse the internet and communicate with your love ones, so using all your discretionary income to invest in Bitcoin might not look too bad but if you do that, you are going to deprived yourself of so many things that are essential in your daily lives which is no proper in my own opinion, investing aggressively is quite good, but over doing it is were the problem is, because you might ran yourself into financial trouble in the process.