Hierarchies are resilient
Tiago Forte writes in A Complete Guide to Tagging for Personal Knowledge Management :
Numerous studies […] have found that people strongly prefer to navigate their file systems manually, scanning for the file they’re looking for, as opposed to searching. Manual navigation gives people a concrete structure to navigate, with folders and labels giving them visual feedback and control in incremental steps […].
Searching relies on declarative memory — remembering and entering the precise contents of a file — which is a higher-level brain function that consumes a lot of energy. […]
I’m in favor of having a well-organized filesystem (see Organize electronic archive by year) that I can navigate quickly. When I don’t know exactly what I am looking for, I can still browse the filesystem and see what I find. If I were searching, I’d have to think up all the different search terms and wade through potentially tons of irrelevant search results.
The search functionality in many products is lacking. It’s either too slow to be usable (Notion) or the search results are mostly irrelevant (Confluence).