PL versions have some lens fitment compromises, EF doesn’t.
Certain PL lenses just don’t fit. Older style glass in almost all cases with deep rear elements and steep ray angles.
Certain lenses vignette on VV, usually longer focal lengths.
Certain combinations of camera accessories will obstruct fitment and require changes to your rigging.
…also, people will be jealous of your cool gear and say mean things about you in the crafty line.