I agree GIFs are good in some cases like a small demo on Github. They are also supported pretty much everywhere.
It's probably an anti-pattern when:
- There's more than 1 GIF playing on the screen (can be disorienting)
- The GIF takes too long (you can't rewind, so dont make them too long)
- Bad quality GIFs can be annoying and useless
Probably some more cases...
