The only benefit of having airplay vs airport express is that the wireless is built in. I use an airport express with a digital optical cable at one end for my stereo receiver and a 3.5 size at the other (digital, not analogue) plugged in to the airport express.
I guess B&O would have known about airplay because companies like Apple need companies like B&O to adopt it in their products. I would also suggest that the licencing fees would be outrageous for B&O. Which kind of reminds me why apple doesn't integrate HDMI (they don't want to pay). Apple is too closed and I agree with Trip's comments earlier about integrating this kind of tech.
Can't wait to touch one in the flesh and listen to it.