[pornel]

GIF has no seeking at all. It's entirely sequential, requires single-threaded decoding start to finish.

OTOH every video format has keyframes, is more friendly to post-90s CPUs, and recent formats are parallelizable.

You have only been able to notice how "heavy" VPx is because lengths and resolutions used with this format are way beyond GIFs capabilities.

Try encoding a mere 10-minute 30fps 1080p video in a GIF, I dare you.