In case you iOS users haven't heard, Facetime has a baby sibling and it's name is Facetime Audio. But despite the misleading name, you don't actually see the other person when using this feature. Weird right? This option is solely audio based, and is essentially making phone calls over the Internet while using the other person's normal iPhone number.
To take advantage of this feature, choose the phone icon next to the FaceTime label in your contacts entry. It uses your data rather than the cell network. (See demo video below.) "What's the benefit of this?" you might ask. Well for one, you'll be amazed at how much better the audio quality of the call will be. In addition to the superior sound, Facetime Audio is great for when you're overseas and want to talk to your friends and family "back home". By simply connecting to the hotel wifi, you can speak for as long as you want without incurring those ridiculously expensive international rates from your service provider.
Useful and a money saver. We'd say that's pretty cool.