If you foul a ball off that the game deemed was a pitch in the strike zone, the game rewards you with vision points. But if the pitch was outside of the strike zone there is no rewards outside the fact that you are still alive at the plate. It's not that complicated. The game tends to reward you when you swing at pitches inside the strike zone and tends to punish you when you swing at pitches outside the strike zone without being punished.
With that said, I noticed in an MLB 20 stream where the game punished the batter for taking on a pitch that was a called strike. It never did this in MLB 19 (or earlier) and we should be allowed to take as many pitches as we want as long as it is not the third strike.