https://en.wikipedia.org/wiki/Trinity_Cathedral,_Saint_Petersburg

Basically, in the English language, the cathedral is sometimes referred to using a translation from Russian (Trinity), and sometimes using a transliteration (Troitsky).

absolutely; proper integration into the editing workflow is one of our longer term goals. In the meantime, it may be useful to experiment with more direct invocation of UW in the article context; you can see an example of this here: https://en.wikipedia.org/wiki/List_of_rijksmonuments_in_Bloemendaal_(town)

I haven’t done or seen any quant break down of UW uploads by categorization (ideally comparing also the likelihood that a newbie would use categories with both tools). The general problem with categories is that the common language for categories is English, which excludes lots and lots of people from being able to usefully categorize content. This is a big part of the reason why categories aren’t more prominent in the UI. I hope this is a problem we’ll be able to solve in the long run, e.g. by developing a multilingual tagging system that’s tied to the Wikidata concept database.