Only Apple supports this. Like, literally just Apple. I hate Chrome, and even Chrome doesn't support this. Firefox? Yeah, zero support.
So for these reasons it's 100% not viable right now. If you get the support, I'll consider it for my websites, and tell my colleagues about it, though.
Let me know if it's incorrect, I'd be very interested to learn of new options for the web space as a developer. This said, I googled Firefox and it came back with only "experimental support" for what I think may be an alpha release (version number ends in "a").
It has more efficient lossy compression then JPEG. It has more efficient lossless compression then PNG. More efficient compression then gif and supports animation like gif. It allows for more colors then any of those 3.
You can have a single for extension for photos graphics, and animations and costs less storage and bandwidth saving money and making a better ui.
Webp supports 24 - bit RGB w 8 - bit Alpha channel. It also has better lossless and lossly compression. And it handles transparency and animation better than other formats at a smaller size.