If you have a VoIP phone, like Skype for example, you can hold a conversation at 35,000 ft.
Here's a interesting dynamic: Planes that cross the ocean are starting to offer Internet access via Wi-Fi. It's not cheap, somewhere in the neighborhood of $25 for the duration of the flight. But that's not the issue here. The issue is that if you have a VoIP phone, like Skype for example, you can hold a conversation at 35,000 ft.
Assuming that the cell phones won't interfere with the plane's controls (which we've been assured they won't), the chief complaint with the phone use is that having multiple loud conversations with people packed into such tight quarters can lead to headaches on top of headaches, literally. The same problem exists with VoIp phones.
I don't think that's what Scandinavian Air had in mind when it decided to offer Internet access. But I guess if you pay your twenty five bucks, you're entitled. I just hope you're not sitting next to me.