People love to discuss the positive effects of both miniatures gaming as well as tabletop gaming in general: Hand eye coordination (painting), patience, teamwork, maybe some social skills. Sometimes these can get exaggerated a bit but I think kids certainly all benefit from a hobby that at some point requires sitting down and reading a book :)

I think on a practical level, I definitely learned a bit of patience and it was a massive help for my language skills. But the real benefit was a realisation, namely that you could in fact just sit down and make things. 

I suspect this is one of those things that you can get from a lot of different places. Music seems obvious but while I've always loved music and I had many friends who played, I never had any interest in playing on my own. If you get into a craft at a young age, you no doubt have the same experience as well. I liked to draw as a kid and was in that middle ground of "better than the kids who didnt draw, worse than the ones who worked at it" but it was just something I liked to do for fun, I never had an interest in really bettering it.

But with tabletop games, it was different. Maybe it was interest, maybe it was seeing so many different ways to do things, maybe it was because tabletop writers often explained their rationales to the reader. Design columns in White Dwarf no doubt was a big impact with the likes of Jervis Johnson, Andy Chambers and Gavin Thorpe explaining their thoughts. Later, I would flip to the back of a gaming book immediately and see if there was a "designers notes" chapter. I still put one in all my books when I can, to pay it forward to the next kid who has that same feeling. 

It made me realise that these things are not the result of an elusive and secretive process: They are things people just sat down and did and if they could do it, so could I. There WAS something magical about the process which is working on something and then seeing it "carried out" on a table. I expect computer programmers feel the same way the first time they write code and see it work on the screen.

I suppose tabletop games also had a lower barrier of entry in that you just needed a pencil and a piece of paper. But I think the exact topic is perhaps less important than having the realisation to begin with. It doesn't matter if you intend to become professional at something or even whether you are ever any good at it. It matters that we can sit down and make something on our own.

I think that is huge.