Bocksi is popular because she is very attractive and intelligent. Also wealthy. And strong. Let's not forget her practical external lungs and the skin pockets at her ankles. Oh and the gastrovascular cavity where you can insert your reproductive organs is of course her strongest point.
All in all she's one heck of a girl, and rightfully deserves the title of Queen of the Universe.
Tabby compared to Bocksi is like a cheap tavern whore compared to the embodiment of love.