We'll have to see how much Nokia wants to appease their carrier partners to take advantage of their existing billing system. I (think) I've read that they want the Ovi Store to be able to bill your purchases directly to your telephone bill. That means the carrier will want some % cut from the revenue for this service, and as far as I know they usually want big % because they're used to products/services with high profit.

On the plus side, if this pans out, we won't be bothered with entering our credit card details on purchases. We just have to brace for our monthly phone bills (plus apps).