Viral 'I'm not a cat' filter is decades-old software
It’s hard to find out why this feature exists from a quick search, but I suspect default avatar (on webcam level, no less) could be an interesting safety measure rather than just a gimmick.If properly implemented, this makes it impossible for the user to reveal their face by accident or from inexperience. Even if laptop operator ends up with some shady app that allows strangers to video call, mucking with system avatar settings would be required before their actual appearance can be seen.