When albums contain featured albums artists
Sometimes albums are credited to multiple artists, and with the default Add all contributing artists to the album artist field option set all these artists will be used in the album artist field for songs of this album.
But sometimes we are just interested in the main album artist so we can ignore these additional artists by selecting the Only use main artist in the album artist field and discard other artists option.
Note when the album is equally credited to multiple artists then the multiple artists will be added to the album artist field whatever option is selected, the options only have an effect when there is a main artist and featured or guest artists.