My experience is that the can / can’t be improved buttons are a bit annoying, for reasons related to this discussion. There doesn’t seems to be any general consensus in iNaturalist about what these buttons mean and when they should be used, so I don’t really think they convey any information. However, when I encounter plants in “needs ID” that already have a bunch of correct IDs on them, it’s usually not because the observer opted out of community ID, it’s because someone clicked one of those buttons. My response is to click the opposite button and move on, not to add another superfluous ID.
It’s not a big deal either way, of course.