However, preference matters. Having a bat in your hands that you think will help you hit the ball better WILL help you hit the ball better. Also, if you are getting 1 mph better exit velocity from one bat over another, it becomes a difference-maker for a player who is already banging the ball to the fence. One extra mph puts more balls on the other side of the fence.
To build on that, not even as much with the over the fence part....but that extra mph or a few mph may turn a ground ball that someone gets to, into a single. Or a drive that gets caught is now out of reach and down. Or a single into a gapper by an outfielder.
Reminds me of a quote by the best homerun hitter to ever play in the minor leagues...Crash Davis
Know what the difference between hitting .250 and .300 is? It's 25 hits. 25 hits in 500 at bats is 50 points, okay? There's 6 months in a season, that's about 25 weeks. That means if you get just one extra flare a week - just one - a gorp... you get a groundball, you get a groundball with eyes... you get a dying quail, just one more dying quail a week... and you're in Yankee Stadium.