> a digital cable means you no longer have to rely on the form factor/budget constrained DAC included in the device itself and can go for DACs of your own choice. That doesn't necessarily imply improved audio quality, but it means you have more control over your audio quality.

That's nothing new though. Those have been available for years. Some quick examples:

http://www.guitarcenter.com/IK-Multimedia/iRig-HD-Studio-Qua...

http://www.guitarcenter.com/Apogee/Duet-for-Mac-and-iOS.gc