I do use the spreadsheet to find people who know my small fandoms and are interested in helping me proofread!

I find the other tabs (general spag, topical knowledge) less useful, personally. Like, if there are a dozen people who can all volunteer some proofreading without fandom knowledge, should I pick randomly? And when it comes to other topics there's not always a consistent way to sort/filter/decide what kind of "expertise" I personally need to have about something before it's worthwhile to offer and not duplicate other people's specialties. (I appreciate that this may just be me, though.)