Data is just data. It’s what you do with it that affects the end result of a game like baseball.
Baseball is and always has been a statistically driven game. R/L splits for batting average, on base percentage, slugging average, ERA, and WHIP are for me the most useful stats. The home ballpark effect is a real thing.
You can dive deeper but you have the be careful about drawing conclusions based on very limited data points. Case in point would be specific batter-pitcher matchups. I mean, how many times does a batter face a pitcher in any given season? Only a handful really so what conclusion can you really draw from Bob Uecker’s lifetime batting average vs. Sandy Koufax? He hit Sandy really well but are you actually going to make an in game managerial decision based on that stat?
Certain stats are very useful but many are just merely interesting talking points for the announcers. I think that a manager has to know his guys on the human level and gauge certain moves (both hitting and pitching) based on a myriad of things from yes – certain statistics – but also things as esoteric as; ‘How is my guy feeling today’?
I really believe managing a baseball team is equal parts statistics and ‘feel’.