I organise my music in folders. Most of it is not tagged, but has informative filenames. It would be too much work to tag it all (yes, I can write a script to do it, but still). Plus, I haven't seen a working tag "hierarchy" in any player -- ie, first I choose to see only classical albums, then only a particular composer, then the particular recordings. They dump all genres / all albums / all performers together and it's impossible to navigate even if it's all properly tagged.
So on linux I navigate manually to the directory I want and play it (usually on the command line). On Android I'm still looking for my ideal "folder player", but there are several that are "good enough" for me. But there's no way I can manage my music collection on an OS that doesn't "expose the filesystem".
I'm fairly sure that many people will say the same of books, photos, etc -- they would prefer to organise them hierarchically themselves, rather than rely on tagging!