Curse of Bidning does not affect Mobs

I have found two unexpected behaviours with the curse of binding enchantment:
1: Saddles, horse armor and carpets with the curse of biding can be put in hores' and llamas' inventories, but they can also be taken out of their saddle/carpet slots.
2. Zombies, Skeletons and Pigzombies that pick up armor, enchanted with curse of binding, can pick up better armor if it's thrown at them (switch binding leather chestplate for diamond chestplate). Players can't take of binding armor, which is why it seems strange that zombies can switch it for better armor.