You could spend the rest of your time learning several languages, advanced maths, or anything else, really, but you choose to gain muscle --- something that has been useless since the dawn of humans becoming top on the food chain.
i don't know what sort of magical world you must think weightlifting is, but nobody spends 100% of their free time weightlifting (it literally wouldn't work, you would lose muscle)
you're really just making one useless point after the other here