I don't know that my son is learning a ton about baseball from his HS baseball. His team was not very good his freshman and sophomore years, but was better last year and hopefully will be still better this year. His coach is a nice guy, but not the best baseball coach in the world.
What he's learning from HS baseball is how be a leader, how to bring kids along who may not be as talented or as motivated as he is, and how to work respectfully with a wide variety of people. And every time he has an at bat or throws a pitch, it's good for him.
I think it's been well worth it.