For one mishits are more of a pain with a wood bat. I've seen players in game either get jammed or hit a ball of the end of their bat and still hit a decent ball with decent velocity while using their normal metal bats. With a wood bat mishits won't perform that well compared to a metal or composite bat. Not to mention getting jammed or hitting a ball of the end hurts like hell also, then there the added thought that getting jammed or hitting a ball of the end could break your bat. (And a good wood bat is usually $100+ so that's not fun) Usually when a kid gets jammed or caps a ball either their mechanics (bat path) are wrong, not timing the pitch well or they have a lack of plate discipline, swinging at pitches they shouldn't. So a wood bat will expose all of these things. This gives the player instant feedback.What type of benefits are you seeing ?
In my experience while training with my brother it helped tremendously. My brother actually has a pretty good swing, a high level swing in my opinion, with lots of power but he lacked discipline at the plate. He knew that he could pull ever ball pitched to him and drive it with some power. He's 5'10 180 and strong as a ox so he was pretty successful. When hitting with the wood bat the smaller sweet spot exposed to him his lack of discipline as the outside pitches that he would pull weren't going as far and ending up being outs. So now he had a better more discipline focus while taking BP and his at-bats during his travel games, that travels over into his high school games. He's gotten better at using the whole field while hitting, he went from pulling every pitch imaginable to hitting balls up the middle and opposite field consistently. He even has added a few opposite field homeruns under his belt.