Personally, no, I do not have an issue. For still images, it seems that WebP works just fine for everyone everywhere, so I upload just about every still image as WebP anyway. But a lot of apps still don't handle WebP animations optimally, so I like to use GIF for most animations. But through a little testing, it seems like animated files don't actually convert to WebP, so that doesn't seem to be an issue.
some testing
GIF I just uploaded, which ended up as GIF:

AVIF I just uploaded, which ended up as AVIF:

JPEG I just uploaded, which ended up as WebP:

I am glad to see that it is customizable by the admin. I am not actually an admin myself at all, but I know that different admins tend to have different opinions on the issue. Notably, lemmy.sdf.org actually works in the opposite direction: any WebP image uploaded gets automatically converted to PNG, which I assume is a philosophical choice due to WebP being controlled by Google.
