Perhaps it's relevant to look at how it was introduced - as a "package deal" with many, many characters from medieval cyrillic literature, as described in this

Perhaps it's relevant to look at how it was introduced - as a "package deal" with many, many characters from medieval cyrillic literature, as described in this proposal https://www.unicode.org/L2/L2007/07003r-n3194r-cyrillic.pdf https://www.unicode.org/L2/L2007/07003r-n3194r-cyrillic.pdf It certainly made sense to include this package in Unicode, and the vast majority of those characters certainly should be in this proposal. You do have to draw the line somewhere, and obviously those close to the line will be debatable, no matter where you chose to draw it, like this particular symbol - but once you've decided that you will include the one-eyed O (small and capital) and the two-eyed O (small and capital), then putting in the many-eyed O as well to complete the set doesn't seem so far-fetched.