For all the fanfare WordPress 5.8 got, the bulk of their more than 300 edits/updates were focused on Gutenberg and the new template system. And, in some ways, why shouldn't it - that's the direction they've been headed for a while.
I have mixed feelings on the release as WordPress, from the very early days of Gutenberg, said they were not going into the page building market, but here they are.
All that said, Gutenberg is still very much a feature lacking rollout, when you compare it to Divi, Elementor and others. I don't think you'll find any designers swapping to Gutenberg any time soon.
Personally, I wish they would have kept the page building tool as a plugin and not built into the CMS, but that's just my own thing.
As far as WebP, this is something people should have been using for at least the last 5 years, and could easily be implemented using Plugins or 3rd party services. Allowing people to upload WebP images is nice, I just hope people remember to also upload their JPGs for places like Social Sharing which, while they do use WebP themselves, they're still used to seeing JPG/PNG as the featured image in the share screen.
For us, we've used the "Picture srcset" which allows you to define different size images, and WebP if the browser supports it. There's really no reason why that shouldn't still be the standard.