@InsignificantThoughts what would be the practical and technological difference between the two for them to exist separately?
@hideki AFAIK 404 not found means it wasn't found for whatever reason, and 410 means it was deliberately removed and won't be back. If you get a 404 it could be just an incorrect URL, but with a 410 you know you are at the right place and it just isn't there anymore.
410 can help to remove results from indexing as opposed to keeping a 404