This is what made me hold off on preordering.
It seems so ill-conceived, and I can't imagine how it will work. Does in-game audio get piped to your phone? If not, what are you supposed to do? Have two sets of earbuds, one from your phone and one from the device?
Also, what's with the console's lack of an ethernet port? Everything I've seen suggests that Nintendo did not prioritize online play when designing the Switch.