I totally understand your point that there are many excellent DAPs now available, and wireless isn't the be-all and end-all of music listening (I, myself, am quite old-skool), but, when suitably configured, it can be incredibly versatile, and will become more and more widely-used, both mobile and in-the-home.
It's important to remember that, although Poly offers wireless functionality, it will also read music at the highest resolutions one can reasonably find, from an inserted microSD card, and feed it
directly to Mojo, but controlled by a smartphone. There is no DAP on the market, no matter how expensive or elite, which will embarrass Poly+Mojo+microSD, in relation to non-wireless music-data-crunching. Not in terms of level of resolution of music data input, nor in terms of resolution of reconstruction of the original analogue waveform that was encoded digitally.
Undoubtedly, Poly won't suit everyone, but, even as someone who isn't a wireless fanatic, myself, I feel people may be underestimating how flexible Poly can be.
I'm as interested as anyone else, as to how Poly will be received, in the fullness of time, and after the reactionary arm-waving has calmed down and people taken a serious, in-depth look at what it is actually capable of.