I haven't really followed this technology so I'd like some education. What is the big deal about wifi calling? Isn't using Skype just as effective? http://www.phonedog.com/2015/09/17/att-wi-fi-calling-iphone-delayed
It's kind of summed up in one of the last statments, "...Wi-Fi Calling is a big feature because it lets you make and take calls over a Wi-Fi connection, which can sound better than cellular, especially when your cell connection is weak....". It's free, where Skype cost money.
@palandri: Ok, I get it. To use Skype free, both the caller and target need to be 1) in a wifi area, 2) calling a Skype enabled device. @rjniles: You are correct. However, for a small cost, it is possible to use Skype to call any phone, including landlines.
Wi-Fi calling is pretty seamless on my Moto X. If in range of a hotspot that I have logged into previously, calls are placed and rec'd over Wi-Fi. In my case, these are mostly cable company hotspots.