-0
I don’t think we need animation in most cases, and it’s often abused and if we do we can always use some videos (also to be limited in usage as it’s a pain to maintain). The example at https://www.xwiki.org/xwiki/bin/view/FAQ/How%20to%20use%20a%20custom%20font%20in%20XWiki clearly doesn’t need an animated GIF which brings no value IMO and makes it harder to maintain. You could simply show 2 screenshots (or more) of different fonts used.
I’ve noticed that some developers have taken the habit of only putting animations in release notes and I find it painful as a reader. At minimum, I’d expect a fixed screenshot and if needed an animation on top, but not just an animation. For example: https://www.xwiki.org/xwiki/bin/view/ReleaseNotes/Data/XWiki/16.6.0/Entry001/ (it’s hard to see at a glance where the source button is located and what you get when you press it)
Definitely -1 for me. There’s a reason to have the size guidelines and whether the image is animated, whether it’s a video or whatever else, the guideline remains.