Because it’s old and easy to handle. Yes it’s wasteful if you convert whole videos, but really anything under 10s with low rez is easily handleable by pretty much anything. Gif was the first animated format and that’s why it’s big. Also early internet forum days were absolutely plastered with pixelart gifs that ran for minutes and barely swalloed 100kb. You can get a lot of bang for your buck if you save on pixels and framerate. But ofc a 60fps render of some 4k bluray clip will eat your memory. Contrast that with 16×32 px gif that runs at 8fps.

Centralisation will always set in due to sheer complacency. I mean it has already happened. The main player in the reddit-like fediverse is lemmy.world
No other instance comes close to the size of lemmy.world
I also disagree with Metas method of tracking and monetising every last bit of data (I’m trying to get rid of their platforms myself) but to expect the fediverse to be a balanced mixture of access points is just daydreaming.

Boom boom boom! I like it with my doom!
Beans saved my life in the past yaer