It supports transparency, animations, and compression, and seems to look really good even with very strong compression. It's a shame that, despite it coming out 13 years ago, it's still barely supported by so much software.
Sounds to me like people need to stop supporting software that doesn't take the time to update. WEBP is great, and I haven't run into a single program that doesn't support it, personally.
Okay, perhaps. It's been a little while since I've tried it. While unrelated, it took Adobe 3-ish years to implement support. That's hardly acceptable, and isn't really defensible.