Not problematic. It just needs extra steps to make sure it doesnt deteriorate. It needs extra care in comparison to like cotton.Ok fine. Take a figure such as the old Sideshow Anakin which is notorious for rotting. Not all old Sideshow pleather has broken down like that.
Plus saying that all pleather is the same is just obviously a ridiculous statement. It would be far more accurate to say in general that it is a notoriously problematic material.
Its like leather seats in my cars. I have to apply leather conditioner so it doesnt start flaking and cracking. That doesnt mean its "problematic".