Yup. Two crewman extras of the same sex holding hands on the Rec Deck or Ten Forward could have been a start a loooooong time ago.Technically, she wasn't an extra, because she spoke.
I agree that extras don't do as much, nearly as much, as main characters in terms of representation, but extras are nonspeaking.
But on the other hand, all roles are something that one can point to to say, "See, it does happen in the Star Trek universe, and we can see it."
Similarly, a blonde woman with a hair bun or beehive handing NuPike or NuKirk a PADD or coffee in the reboot would have been a start. It's a shame that start for Chapel was also an end grrrr.