Yes you are right, it is more better to invest only what you can afford, and if you are truly investing what you can afford, you wouldn't have to let go of smoking or drinking just because you are investing in Bitcoin, those are fun thing to do if you are a smoker or you drinks, it's only when you are investing above your means that you will be stopping things you see as fun just to meet up to your investment expectations.
So what am trying to say is that as long as you are investing according to the level of your discretionary income you will be very ok, and you wouldn't have to stop things you sees as fun because you want to invest in Bitcoin.
But let me know that certain forms of fun can be a distraction to our Bitcoin investment. Some types of fun are just wasting money, and if a new investor doesn't stop it, they may not own up to it and concentrate more on investing in Bitcoin.Let’s just use an example: those who say they are gambling "for fun did you know that someone can become addicted to gambling? Instead of money going into Bitcoin investment, it could be diverted to gambling, which could even stop Bitcoin investment altogether.Also, as you mentioned with smokers and drinkers, some people spend money on expensive alcohol and cigarettes. While it may seem like fun, for a new investor, if that money were used to buy more Bitcoin instead, it would be much more beneficial.So, I would just say that if someone is a new investor, it would be better to stop these fun things that is not neccessary and will benefit us.