It's true, they don't, but if showing a teaser puts people over from buying a PS4 to an XB3 this holiday, then it's a clear win. It doesn't make much difference in terms of what they can show in the future, next E3 they can reveal the game with in-game stuff, it's not going to lessen that at all.Very low. Microsoft won't need Halo to sell Xbox the first holiday.
It seems like an easy win.