Cham, about your original statement, CDMA is being decommissioned not just in Canada but in North America as well, which means USA. CDMA coverage probably used to be very good at one time, but CDMA is a 2G technology, and all the major players stopped expanding that coverage long ago. 3G and 4G coverage is now the dominant standard for all networks in North America, does not mean 2G CDMA is gone, it still exists in small pockets but its at the end of its life.
The phones that you are talking to have a feature called Wi-Fi Calling, its not really new, it's been around as early as 2008/2009, well at least that is the first time I've used a handset with that technology. Basically, when the phone does not find sufficient 3g or 4G cell coverage, it will connect to a wi-fi network to complete calls. so this is great for people who live in basement appartments where there is no cell signal or on the border of coverage, they can still make and receive calls and the network treats it like they are on the network.
bell mobility certainly supports wi-fi calling, but you need a phone from bell with the feature built in to use it. Sometimes phones from the states have this feature but that does not necessarily mean bell enables the feature here in the bell equivalent version of the phone. please tell us the make and model and we can check for you