Last week, I tried to send a picture using QSSTV and it wouldn’t open the webp image I saved from a website, so I had to convert it first.
Up until last year, Libreoffice didn’t support webp and many Linux distros haven’t updated to the version that supports it yet.

Even GIMP and ImageMagick didn’t support it for quite a while. Before they supported it, it was almost impossible to do anything with webp.