This never occurred to me. The idea that recipes, financial information, and work-related technical papers should all go in one database struck me as inherently ridiculous.
Then once you accept that some topics belong together and some don’t, the remaining debate is about how granular to make the divisions. Those are databases, then groups within them. Tags come in (for me) at the level where things can potentially belong in more than one place, or where topical divisions conflict with some other grouping that’s important for me. (Vendor vs. date, say, for financial information.)