You have to remember that sometimes when that shiny new CSS feature comes out, it is underspecced, with unhandled corner cases – “just do what Chromium does” is not a standard – or is it? Having multiple implementations of a spec prove that it is interoperable - without that, you might have a good spec, or you might have a spec that says “whatever Chrome does is what is expected”. Not sure that is what we want from new CSS (or any) features.
Yeah that’s not true.