I think it is because Nintendo's approach to E3 really feels like it is going to be such a non-event. It's almost like they're saying: "we don't really have anything interesting to show this year, so here's another typical Nintendo Direct". I'm not saying that it will be like this, but it sure does feel so downplayed compared to what everyone else is doing. Sony on the other hand is trying to turn their E3 conference into such a huge grandiose even by playing this thing at local cinemas.
I honestly cannot imagine any possible way this could backfire.