Example - I want to organize my books/photos/music etc. in directories, in order to be able to use the same structure across various devices (some of them can have very different semantic approaches, not compatible tagging and etc.). Directory structure remains one solid interoperable organization approach since filesystem abstraction is virtually the same across most OSes (especially POSIX ones).
So, I need to be able to easily do the following:
1. Creating / deleting directories.
2. Moving files / directories to another directory.
3. Renaming files / directories.
4. Creating files knowing which directory they go to after the creation.
Doing search on directory name to access it in the interface sounds rather awkward to me and very non optimal from usability perspective. I'd prefer just to ssh to the device from another computer and move stuff in the terminal, rather doing the above. You once noted, that device is supposed to be for the user (make play live) and not forcing user into some predefined consuming mode. It means there should be no artificially imposed deficiencies which hinder the workflow. Usual KDE approach (at least on the desktop) differed from Gnome in a sense that KDE didn't dictate "the right way" forcing all users either to bend or to leave. Rather KDE offered some sensible (from designers' perspective) defaults, with giving an option to do things differently, if there is a real need for it. I consider it a major plus for user friendliness in KDE. Why should Plasma Active be devoid of the same user treating.
So the way I see it - Files should offer both modes with easy way to switch between them. Triggering filesystem view mode using Search method doesn't sound normal at all.