In a few instances, I have found myself questioning this very same thing. Clearly, Google Voice is pretty cool. However it is worth noting that it is hardly a standalone application. Basically, it’s voicemail with reverse call forwarding.
As a Skype user, I have found that I use this service much more. Why? Because it does not require me to provide another number to ring through to when someone wants to call me. It’s right there, running on my PC anytime I want to use it.
At the end of the day, I see Skype failing big time in the mobile space while continuing to grow on the desktop. And I see the reverse happening with Google Voice.