I'm talking in the context of on a general webpage; not about it being supported on a site or not (that's a UX perspective by technicality, allowing users to upload it or not as media).

That's the reason it exists; better compression at the coss of less quality loss while being animatable.

think of it as an alternative for etcetera.

Better compression (tldr faster load time) and less quality loss. That, and WebPs can be animated.
PNGs are more for infographics, insane detail images, yadayada.

no, it automarks memes with a swear in them as nsfw
try it

likely due to the lone swear word