In allegiances, the MC could be described as:
Beautiful, slender silver tabby she-cat with ice-blue eyes and sleek, glossy fur
While others can be:
Black tom

* Look. If you have one MC and it's in their POV, the allegiances might be most extensive description you'll have of them, so it makes sense to go all out (even if adjectives like "beautiful" and "handsome" are a bit funny)

And if you have characters whose main purpose is to die early or remain background for whatever reason, yeah, probably best not to clutter up readers' brains with useless details.