[Aardwolf]

Or can be abused, without pet, to go directly to your desired floor without being interrupted by those passengers at other floors.

[pjerem]

In Japan, where this pet mode exists, honor and respect of social rules are something, and I doubt you would take the risk to be seen leaving an elevator in pet mode without a pet.

[DonHopkins]

Does a Tamagotchi count? ;)