...Some people use their extra money to gamble, club, drink, womanize and many more but it's wise for you not to use this funds for consumption purpose. ..
Investing with your discretionary income allows you to pile up more bitcoin for yourself overtime and hodli till your desired time.
But in any case, you should not limit yourself to entertainment, because living with the sole purpose of accumulating more bitcoins is pointless. You have provided a good list of what you can spend your discretionary income on, do not limit yourself, because life is short)
Not at all, because I cannot use all my discretionary income to buy bitcoin. At least I have a percentage of my discretionary income that I put into bitcoin weekly. This is why DCA is the most flexible method that anyone can use to invest without stress. The most important thing is that you should keep your bitcoin purchase ongoing irrespective of the amount that you are using to buy bitcoin. When it's festive periods, I don't buy bitcoin because there will be a lot of expenses on ground. You don't need to punish yourself because you're investing.