S1 E16 Pinkie is wearing a foamy hand! Let me repeat. HAND! They could have easily made it a foamy hoof, couldn't they?
Honestly, if that was a hoof, would you have recognised what it was meant to be? That's probably why they used a foam finger, not hoof.
Exactly what I was going to say. I don't think kids would recognize a foam hoof. But we all know what a foam finger represents. Plus Pinkie breaks the fourth wall like it's nothing.