Slightly harsh to say there was no USP. Faced with a likely substantial loss of passenger feed from bmi (or sharing customer info with the arch rival) and not having a strong backer in the shape of Delta 2 years ago, Virgin had to at least try something. The alternative would have been their Heathrow ops having to survive entirely on London point-to-point.
Didn't work out (yes, I know the different terminals didn't help) but one shouldn't be too negative for VS at least giving it a shot.