Re: As phone?
T-Mobile and Sprint supposedly offer Wi-Fi calling, but I'm not sure if it works the same as AT&T.
Originally Posted by DevilishBanker
At least on AT&T, if you have an iPhone and an iPad on iOS 9.2, you can set up Wi-Fi calling on your phone and send/place/receive calls and texts. Whether your phone is on or off, your iPad will get all your calls and you can place calls using your AT&T phone number. For texts, your phone has to be connected to AT&T's network and must have a data connection (Wi-Fi or cellular).
I thought that was pretty awesome. I just got a cellular iPad Air 2 for $99, so I gave my old Wi-Fi iPad Air 2 to my dad. After setting it all up, he gets all his calls and texts on his iPad as well as his phone. The phone calls just go through the FaceTime app.