Originally Posted by
Iscah
It's an oddity of the character creation template and how the same settings have been used across different character designs.
As a general rule, the aesthetician lets you change "decorative" elements of the character but not their actual body.
Limbal rings are an exception because for most races, that data element is used for race-specific tattoos, or for Wildwood Elezen's earrings. So because it's the "same" setting, you still get access to it.
(The inverse being why Hrothgar don't get a special exception on being allowed to "change their hair" by changing their face setting. They'd probably have to let all races access the setting.)