I’ve always considered “grit” an attribute related to character, not educational achievement. You can’t quantify someone’s grit level, while learning can be quantified by testing.
Yes. They basically want to be able to say that if someone persists through trying something (despite repeatedly not being successful) then that constitutes lots of “grit” points, so they also should get into schools and programs that others qualified for via actual success. So they made a scale, as people do who want to publish things, as they only do because that is what they are supposed to do, not out of real interest or a sense fore the actual utility of their publications.
I would honestly rather give 5 to 10% of admission approvals over to the “gut feel” of experienced faculty (including being good at knowing who the BS artists are, because there are a lot of them!) than to permit the redefining and repurposing of a word into a scale that is much more abusable than useful.