I am not sure if I understand the question.
If musicbrainz or discogs has an album, regardless of its format or song/artist list, set as a compilation, then why would you not want to have songkong/jaikoz match it?
I would think one would expect it to match to what ever musicbrainz has it set to on their end.
For songkong, it would make sense to just default to the info that is provided to it. For jaikoz the same thing with an option to not update that field for those that want to update it manually.
If the question is more so a theoretical question on what people think a compilation is, that could be a very long and debated topic. With compilation only being a true or false option, there really isn’t a whole lot a choice there. This makes it so one has to force themselves to decide if greatest hits, anthologies, discographies, boxsets, collaborations, mix tapes, remix albums, etc, should be considered a compilation or not.
I typically will consider any album that has the same exact recording on it that have already been officially released on a studio album previously as to be a compilation. Not including different pressings, country releases, or mastering of the same studio album. I do this for both single artist and multiple artist albums. Basically any album that may give me duplicate songs from the studio albums I already have.