Nate appears to have uncovered something really interesting. Platoon differentials are based on the pitcher, not the hitter (mostly).
This is a reason to pay attention to platoon splits again, if they’re based on lefty hitters (righties don’t show no bias).
Nate finds some specific uses for this data in his article, but I’m not sure it’s going to matter as much in the real world as it might in roto. Any time it’s better not to play than to play, fantasy owners take notice.