In the song "Be Back Soon," from Lionel Bart's musical Oliver!, both Fagin and his boys (The Artful Dodger, Oliver, et. al.) distinguish the phrase from "goodbye."
Cheerio, but be back soon.
I dunno, somehow I'll miss you.
I love you, that's why I
Say "Cheerio," Not goodbye.
The connotation being the departing remark is more familiar than formal.
Also the name of a week long calligraphy retreat held in the Blue Ridge mountains of North Carolina, where participants get to spend a week with world reknowned calligraphers. Founded in 1984 by Jim and Joyce Teta.