I applaud Markus for his critical analysis of the benefits of call through. He has identified the core reason why Call Through is a big benefit to consumers.
In making his analysis Markus takes on pal Dean Bubley, who has a slightly different perspective. My view is that VoIP is present in both arguments, but that VoIP plus existing end points makes it easier for people to use it without the pain of knowing the are switching.
Client and friend PhoneGnome CEO David Beckemeyer makes a similar point on termination, of calls over the PhoneGnome network. While he calls it minute stealing, I call it termination diversion.