@Terrificli -- You are right, but I do believe the tuba and euphonium have a lot more in common with each other than they do with the baritone. I have always thought of the baritone as kind of a bass trumpet. It has more range and is more flexible than either the tube and euphonium and, as such, adds something completely different to the bass parts of songs.
Don't get me wrong. All three instruments are very important, but the baritone is its own kind of strange animal.