As a desktop Linux user, I'd guess it's harder to make it work right (because of, among other things, driver issues) and it affects a smaller portion of the user base of Firefox. Oh well.
Fortunately it's easy to opt in to, and in my experience works well on an oldish Intel chip.
Unfortunately, it fails hard with Wayland, putting no pixels on the screen. (In my experience) But I'm using it happily through XWayland.
No, only tried on stable. Looking forward to testing 67 when I get the update.
I should clarify that I am talking about the situation when running Firefox with GDK_BACKEND=wayland.
UPDATE: Ooh! Firefox 67 in my package manager! I am happy to report that I am now able to use Firefox with WebRender on Wayland directly. One glitch so far: It leaves a one-pixel row transparent at the bottom of the screen. Weird :)
Fortunately it's easy to opt in to, and in my experience works well on an oldish Intel chip.
Unfortunately, it fails hard with Wayland, putting no pixels on the screen. (In my experience) But I'm using it happily through XWayland.