Haha!!
I first heard it about 10 years ago coming from a very preppy / yuppie couple from Sydney (I worked with them). They both sounded so mindlessly cheerful when they said it, it drove me mad.
The, in recent years, I've been hearing people from all over the world saying it.
Why not, "Love your work!" or "Good on ya!" . . . Oh yeah, we gotta keep them priceless gems to ourselves.