It might benefit Apple and its customers if Apple were to add a VoIP service. Think of a product akin to Google Voice, but with Apple's flair and deep integration into the Apple ecosystem.
VoIP stands for voice over Internet protocol. It's a methodology and range of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks such as, well, the Internet. An Apple VoIP service could be important because traditional phone type service is still very important in our world. Not everyone has gone completely smartphone yet.
However, data caps are killing data-only communications. A video call (if the carrier even allows it) would eat up a lot of bandwidth. Being able to kill the video in my FaceTime call would enable me to keep right on talking and keep my data usage much lower. When I get to my destination, I can transfer the call back to video and/or to another device -- say, the iPad, while I'm having coffee and waiting for my appointment to show.
Perhaps there's some sort of carrier politics or restrictions that will keep Apple from doing something like Apple Voice. If not, having traditional telephony built into my Apple devices including the laptop and desktop would be tremendous. Yes, that would make Apple a direct competitor with Google Voice, Skype and other VoIP services, but since when is Apple afraid to ruffle feathers.