The developer mentions this:
"The combination of a second viewport on handheld screen, very accurate gyroscopes and accelerometers, and front and back cameras seems to offer a lot of possibilities"
Hmmm.. are they mistaken, did I miss something, or perhaps they know more than we currently do, and Nintendo is leaving a few surprises for us in the retail version? He also mentions AR possibilities, which - as far as I know - would be better experienced with a rear camera as apposed to a front one.
I find it unlikely that Nintendo would display/advertise the console without this feature, knowing full well they'll have it in the final retail version... but like the article suggests, I won't underestimate them. We'll see...