seriously lets be real here. there should be an option to hide your tail in the character/equipment window for characters who have them.
you may be thinking "what? why?"
the answer is simple.
sometimes you just want to wear some sort of crazy costume (chocobo suit for example) and not look like you're in the middle of pooping a giant cat or lizard.
also they don't always work well with every piece of equipment.which how much and where they clip.
heck even if it takes a glamour prism to do/set up for glamour plates i'd be all good with that.