Queries kind of suck when it comes hierarchy, do they? And you sure have some folder hierarchy, even if you're not happy about it?
There might be some hierarchy between tags: PhD/laser experiment, PhD/dissertation, but there's rarely a need for it to be more than 1-2 levels deep, so I prefer to suffer the pains of inadequate hierarchy rather than inadequate queries. Or at least I would if I could try it out.
Which use cases would a query language fail to help with?
My typical scenario is multiple copies of something in progress, like traveling with friends, copying photos to each other phones on the way and then downloading the whole mess to one computer. Query language would give me precise information for every file but it's overwhelming.