You are missing the GP's point here.
He is not missing the point. Sure, chess is a good brain exerciser. But there are plenty of other activities that are just as good, but are also actually useful in their own right.
When I was in high school, I learned to play chess well enough to compete in tournaments. I also became a pretty wicked Go player. In hindsight, I consider all of that a waste of time, and I regret it. I should have spent that time becoming a better programmer, a better circuit designer, or a better writer or even better at conversation. Those things would have actually made a difference in my life.
Now that I have kids of my own, I have taught them both chess and Go, but only at the friendly-game level. We spend a lot more time playing with Lego Mindstorms, and writing games in Scratch or Python.