But, FaceTime could also work for the general public because up until now, video calling took effort and planning.
Even with Skype, both parties have to sign up for accounts, exchange screen names, make sure they have computers with a camera, speakers, and microphone. If you're really lucky, the computer will be a laptop. And both users have to be at their computers and signed into Skype to make the call, which means that in a lot of cases a video call ends up being coordinated over the phone beforehand.
FaceTime just requires that you know each other's phone numbers, (when the spec is released, I'm sure big, bright "FaceTime Compatible!" stickers will show up on lots of phones) and, for now, be on WiFi. "Upgrading" from a phone call to a video call is as simple as pressing a button. The "cost" to make a call is so much lower.