Example: Do you paint and/or build because you feel like it, or because it pays your bills? I doubt a child got bills to pay, so why do they paint and/or build LEGO? Code can be art and play too.
I'll go even further. If you're a kid and coding isn't fun, then please stop doing it. The last thing you need is to sacrifice your career to something you don't like doing.
I doubt that building LEGO's has anything to do with building actual houses out of concrete and glass. That's my point. You can't build a real house out of legos and playing with them will not teach you anything about how actual houses are built. Same with programming - you can't learn to build good software by just mucking around aimlessly (unless you are some sort of genius). You have to learn how high-quality software is built.
Or maybe it just seems so to me, because I'm really really stupid and have to work hard to grasp even the easiest concepts :-)
It has very much. I played with LEGO my entire childhood, and I can see it becoming useful for building things in a creative way - but without having to think much becuase I think it's so obvious how it can be solved. With this in mind it's important to try to build things in other ways of course, and that was _why's point - but only if you think it's fun though. In short - as mentioned in many comments now: Try to do things that you find enjoyful, then this play might become very valuable for you or for others in one or many ways.