AV1 is an open and free format, but if people really wanted to replace GIFs they could've done it with H.264 or VP9 or VP8.
Notwithstanding any issues about video codec support in browsers, GIFs will continue to have value until browser-vendors, spec-writers, and webmasters accidentally or deliberately coalesce around a sane ruleset for embedded motion picture completely devoid of audio.
Today, browser-makers have concerns about which videos to autoplay, webmasters' tools for specifying "muted" videos have been unreliable. GIFs completely sidestep that conversation, because GIFs cannot contain audio, and will always autoplay.
Notwithstanding any issues about video codec support in browsers, GIFs will continue to have value until browser-vendors, spec-writers, and webmasters accidentally or deliberately coalesce around a sane ruleset for embedded motion picture completely devoid of audio.
Today, browser-makers have concerns about which videos to autoplay, webmasters' tools for specifying "muted" videos have been unreliable. GIFs completely sidestep that conversation, because GIFs cannot contain audio, and will always autoplay.