Baseball involves a lot of basic athletic skills: throwing, catching, running, and hitting. We have worked on the first three this year, so hitting was on deck (so to speak!). It is a difficult skill to master; even at the pro level, if you only succeed one out of three times, you are considered to be pretty good.
We used batting tees to begin with, and for Middle and Older Kids finished with a game of coach-pitch.
We simplified the rules a bit (no steals or leadoffs, time called once the ball was back to the infield), but even so, baseball calls for sustained attention, awareness of the situation (runners, number of outs) and works on those cognitive skills as well.