Filepath is just unique name that model can identify easily and understand grouping. Uuid solves nothing but requires another mapping from file to short description.

UUID solve oh so very, very much.

You can have several versions of the same set of data object at once - an entire source set for a build, all the names duplicate but tagged with 'revision' so they can be distinguished.

Hard to do that without a UUID at root, to use for unique identification of the particular 'particle' of the particular data set.