More or less, yes, if more people understand one design than another, then the one that more people understand is the right one. We're generally shooting for more than a majority though, we'd want most people to understand the interface, and would also take negative reactions into account.
In our past studies we found people generally understood the buttons well enough, and specifically it was obvious after first use what was happening. But we only compared the current buttons to one other option (which didn't compare well), so it wasn't a very thorough test.
There's more overhead in updating this interface than some others, since we have to get updated translations (to more strings than just the button) and change all our onboarding, which is why we've kind of left it be until we can look at the full set of buttons more closely.