Systems that try to get rid off the "files & folders" abstraction of a file system tend to have much worse usability, in my opinion. I have an iPad Pro, and the lack of true file system abstractions is so painful. Every app has its own way to store and retrieve data, there's almost zero interoperability and it's super painful to copy, paste and move stuff around (I know it has gotten better but it's still so much worse than on any desktop OS).

I'm all for enriching the concept of a file system with additional meta-data (in fact many files do that) but I don't think that needs to happen in the file system itself. For example, software like Picasa leveraged meta-data contained in files to provide a new way of interacting with large number of photos. The author basically proposes to put such functionality directly into the file system, but I'm really not sure if that's a good idea. Right now it's easy to move files between different systems, e.g. from Mac to Windows or Linux. If file systems become meta-data management databases that will become much more difficult.