
Adding UX as a new category in this selection would help differentiate issues that aren't necessarily about the appearance of the given interfaces/apps/... or the core functionality of the products, but rather about behaviours and usability of the interface and flows themselves.
In my opinion how using something feels/works is just as important as how they look, so UX as a new category would greatly help with that.
This would be just another selection option when creating a new suggestion/issue.