Ethnicity isn't important on WPis just incorrect, with the number of articles and subcategories under Category:Black British people. feminist 13:11, 19 September 2017 (UTC)
The discussants in the CFD which deleted Category:Late 19th and 20th Century Revivals architecture and .... did not have full information, such as exactly how this category is used, and how many National Register of Historic Places (NRHP)-listed places have this description. The term is one of 40 most commonly coded architectural styles for NRHP-listed places, as entered into the NRHP's NRIS database and is indeed somewhat a catchall, for buildings built with an amalgam of Revivals styles. The category is useful. There are many architectural Revival styles, and many of them were popular in the U.S. during the late 19th and early 20th century period. Many buildings defy categorization with just one, like "Classical Revival" or "Egyptian Revival" (tho I am not sure these specific ones were among the popular revivals then) or other narrower terms, because they in fact show a mix of the Revival styles that were all in fashion. For individual buildings, if a primary, narrower category can eventually be determined from more sources, it would be fine to revise the categorization to something more specific. It was stated in the CFD that there probably would not be an article corresponding, ever. That is not so, the existing corresponding article/section at Late 19th and 20th Century Revivals architecture exists and could/should be expanded to give more info. .... I had a report once of the number of NRHP listings having this and other of the 40 most common style categories, but can't find it right now. My guess is that there are 500-2,000 possible members of the category.