While Animated GIFs are very inefficient by todays standards, they still have several advantages over all modern video formats:

  - GIF lacks audio support so it's guaranteed to be silent
  - The crappy compression forces creators to keep their clips short
  - GIFs can often be uploaded/attached on platforms that only support images but no video for some reason 
    (like GitHub issues for instance)

Some of those features are actually limitations but IMO there are a lot of use cases for a format that sits between still images and full blown video.

I maintain a screen recording app for macOS that has a very efficient aGIF exporter: https://www.peakstep.com/claquette/

The GIFs on the product page are between 130 and 400 KB.