I dunno. I kind of like trying to judge it visually and waiting for the ump's call.

I can also imagine MLB having similar concerns as the NFL when, for instance, they insisted on removing the line as the ball is being spotted. That is, if they are showing the strike zone and the ump's call seems inconsistent, then it wouldn't be a "good look" for the sport.

There might be trouble with depth perception there. When I watch baseball, I can't easily tell at what point the ball crosses the plate in the behind-the-mound view. When a pitcher throws a breaking ball, I usually have to look at the non-overlay strike zone they show afterwards to know where the ball was when it passed the batter.