This is mainly for classical releases as some customers with classical collections use the artist, and albumArtist fields in a different way so works better with classical when want to be able to search for composer, conductor, orchestra, soloist. They also sometimes use grouping but this field is not modified by default anyway.
So would not update Artist, Sort Artist, Album Artist, Sort Album Artist (unless perhaps artist/album artist is blank)
I don't think its possible to accuraetely identify classical but this option allows users to run to
Run against Classical
and not mess up editing.
Also different but related issue some users don't like sort artists, especially a problem if SongKong only matches some songs because then if there are songs not matched and without a sort artist iTunes can see as a different field, so maybe need additional option of
Dont Populate Sort Artists