I was on ATT for years and never thought about my phone not working if I switched carriers. About 6 month ago I did switch carriers to T-Mobile and although happy in some respects I think their network is lacking a little so I thought about Verizon, this is when I discovered that my phone may not work on the Verizon network since I bought it from ATT. I still can't think of a good reason why apple would make phones that are restricted to certain network, seems they should all be unlocked phones so there is no confusion and if you want to take your phone to a different carrier that should be your choice and not be decided by which phone model you bought.You know that "world" means that it actually will work anywhere in the world that has a cellular signal, yes?
I live in an area where there's full GSM coverage, but I can drive an hour and a half out into a rural area where I would have spotty coverage if I only had GSM.
Which is the only reason I actually care about having CDMA in a phone. If I take a trip to visit my rural relatives, my signal always has a chance of being iffy. If I wanted to sell my phone to someone who lived out that way next year, they might not want it and I wouldn't feel right about selling it to them.
I don't always sell my phones. Sometimes I give them away. Wouldn't want to give one away to someone who might have spotty coverage with it, either.
In fact, there are some neighborhoods that are about 10 minutes from my house, in a rapidly-developing area and I have always gotten a crappy signal (and sometimes, I drop carrier) in those neighborhoods. People who move out there usually get Verizon. And, I don't live in the boondocks, either.
It's really not an issue except that it's illogical until we don't have any major carriers in the US who use CDMA. Can you use the Intel model with Verizon? Sure. Will it perform far worse than the QC version on Verizon? Yes. Which is not good for people who buy phones full price and like to be able to tell their carrier to take a hike if they decide they want to switch.
That's really all it is to me. My iP 7 plus works fine. But, I am on AT&T. For now.