They get you for the phone and the service, the service is crappy at your house, they won't expand the signal to cover you, but hey look we have this $250 box that will allow you to use your phone!
Don't forget that you have to pay for a connection to the Internet to offload traffic from VZW's network to your ISP's network. VZW should pay you for sparing their bandwidth.
You're just offloading it from their wireless network to their wired network.
Not if your wired connection is Comcast. It is only on their wired network if you have Verizon DSL or Fios.
The call has to traverse back to the Verizon network for call termination somehow, so only part of it traverses your ISPs network. That's what I meant.