Sometimes in an album the first track title contains (intro) and the last track title contains (outro). Should we drop them like the phrase (bonus song) since it doesn’t provide any additional information?
I do think usually it provides some info.
Often an intro or outro is a special case of a skit or interlude. Sometimes there are also intros to other songs somewhere in the middle of the album.
Other times it‘s true that intro/outro just means first/last track of the album.