I just bought a new phone, after an unfortunate accident that bricked the old one and forced an emergency trip to the mall. 
 
The new one keeps bugging me to enable wi-fi calling. Why would I want that feature? In case I'm closer to a Starbucks than to a cell tower?
 

You can make phone calls and send txt msgs from just about anywhere in the world. When I was in Iceland I called home just by dialing in the regular numbers and the connection was really good.

If you have an unlimited plan, it probably doesn't matter to you. Otherwise, you can make calls over wi-fi without using up your plan's minutes.

Thanks, guys.
 
I see now that it could avoid roaming charges when traveling. And I don't even have to go very far to find myself in that situation. Without a special plan, calls from Canada can get pricey, and I am in Canada regularly. 

Wi-Fi Calling.
 
Why can't the just call it what everyone else does...VOIP?
 
Remember Vonage?

Yup, I remember Vonage. And Vocaltec before that (nowadays called Magic Jack). Cheap, but unreliable - and therefore unsuitable for business use or critical communications. 

If traveling far and wide, try one those cheap Tracfones and buy some minute cards for it. The phones are only about 35 or 40 bucks and you can use them just about anywhere in the world without paying a dime more than you would at home.
 
Bill

I don't know about other places, but in UK if your phone offers WiFi calling it simply means it'll connect to your phone service provider using your WiFi connection rather than cell tower. From that point it's routed as per a normal call and still counts toward your normal phone plan. This is distinct to VoIP where a PTP connection is made over the internet, such as Skype and others.
 
Pros, if you're in a low (or no) signal area your phone will work. Great in office buildings or at home or anywhere you can access WiFi.  If you loose WiFi connection it'll fall back to normal signal silently.
 
Cons,  can't think of any...

Living in two of the most stupidly expensive places on the planet to make / receive cell calls, I use wifi and whatsapp or skype whenever I can - whatsapp works great for me and I make about 90% of my calls on this
Nigel