I’ve been thinking about this topic for the last several weeks as I participate in discussions, address topics in the UX Bug Feature categories, and create topics of my own.
I think this is definitely the case. Sam and members of the team are free to categorize and tag topics as they see fit, in the interest of responding to the topic and getting to a resolution. If members are confused about these decisions, they can reach out to @moderators.
This is a great example of a topic that belongs in UX. It is small and is specifically about making an improvement to the interface. It’s also a great example of the kind of collaboration between community members and the team that we like to see, that leads to very nice quality of life improvements. 
Continuing on with the example Charlie cited, an area our team team needs to work on is pursuing topics like this to the end so they can be closed. Even this quite excellent collaboration was left with some loose ends. This is natural in the ebb and flow of discussion and collaboration here, and our engineer and designers are busy. As a result UX enhancements sometimes fall between the cracks, no matter how good the suggestion or how small the request feels. After a while @moderators can help identify these and shephard them home.
I updated the description for the UX category to make public what has been our internal approach to this category. This I hope will help everyone understand better what goes in UX vs other categories Feature and Bug.
Discussion about minor display issues and small changes in the Discourse user interface, and how features are presented (including language and UI elements). More ‘quality of life’ topics than anything big.
completed or fixed tags are applied to topics in this category depending on the nature of the topic.
Let me know if this is not clear enough or if you can think of further refinements. I’d like to give Bug and Feature the same treatment but will hold off on that for the minute.