That's interesting. Some time ago I had a similar idea, but with the following differences:

3. Ownership cannot be transferred. A file remains in the same application throughout its lifecycle.

4. An application can give another application read-only access to a namespace containing one or more files.

6. An application can give another application read/write access to a namespace containing one or more files through a transaction mechanism.

Do you see any advantages or disadvantages of both approaches from your point of view?