Only if they're all visible at once. Unlike GIF, which has to do CPU-bound stuff to compute its next frames even if it isn't visible in order to stay synchronized, videos that are scrolled off the screen take effectively zero resources. (Well, they'd take resources to play audio if there were an audio track, but not when they're muted like GIFVs are.) You could have e.g. a Tumblr dashboard loaded with hundreds of screens worth of an infinite scroll of GIFV-containing posts, and your computer would only be worried about the one on the screen at the moment.
Good point, hadn't thought of that. If I'm recalling the differences correctly, GIF will let you layer new frames with transparency directly over old frames basically forever, while video formats have full keyframes at regular intervals that allow you to jump to anywhere in the video by only calculating the chunk since the previous keyframe?
I haven't made any gifs since flashing "Under Construction" signs were a thing on web pages, so it's been a while. Maybe I should put some up on tilde.club.
