If you are really interested in calligraphy, you can cultivate your life and cultivate your sentiment. Because you can't learn calligraphy well without reading a lot, it's easy to cultivate children's habit of reading more.
Even if you are not interested in calligraphy, you can write better words than the average person. A good hand can accompany a child for life, at least during the senior high school entrance examination.
And go, in the era before the internet, can be said to be a good thing, because it is a communication tool between people. Because it is not easy to find people, it is necessary to do it occasionally, so as to achieve the purpose of self-cultivation.
Now you can find people at any time, but only online. If you are not interested, learning is equal to not learning. If you are interested, it is easy to get addicted to it and can't find people around you, which is no different from online games.
As for improving thinking ability, there is no direct evidence. It is true that many children who play Go are good at math, but more children who don't play Go are just as good at math. I prefer to believe that smart children learn Weiqi rather than learning Weiqi to become smart.