Please stop running bloated websites with megabytes of dependencies on my chromebook or Walmart PC with a Intel Celeron that is 6 times slower yes I benchmarked them than my phone then maybe I would consider webp.
All in all though seriously; the only good thing about webp and the only way to get good performance out of it is to make your own site on something like Neo Cities from hand crafted html5, css and JavaScript and not load bloated dependencies.
Plus in general people would rather use png because it can be viewed on everything and some websites and services outright refuse to support webp so why not use png or jpg-xl?