Use of AlbumArtist

[PSH]

I am not sure I fully understand.
All my tracks are tagged with Artist and AlbumArtist. Sometimes these contain the same information and as already observed there is useful intelligence that only displays one instance of the information even though the $album$artist$albumartist is requested.
In the case where the Artist and Album Artist information is different, the text suggests that the AlbumArtist information "overwrites/replaces" the Artist information and one might expect duplication or for the above intelligence to be applied. This is not the case as one gets the three bits of information so I'm happy but confused!