I can sure see how it would be a lot of fun to use it, especially in the off-season, and in places where weather is a big factor. I can also see how following a well-planned program could help a player improve. The only thing I question is how close the “stats” would be to game stats. I’ve scored way too many games to ever believe there wasn’t a huge does of kismet and serendipity involved in baseball. 
The thing that’s always intrigued me about baseball is how the most minute things can and often do affect the outcome. FI, if 2 pitchers threw every pitch 80mph 4 seamers to the same lineup, no two outcomes would ever be the same, be it a batter, an inning, or an entire game.