When you say "micropayments", were you thinking $5 ~ $10 or $0.05? I see this as being able to provide low-value payments to a clientele that can't normally access them. It fixes the major problem they have: inability to credibly demonstrate willingness and ability to pay within the constraints of an online interaction. Banked people can do this fairly easily: punch in credit card details.

(Well, technically, it really fixes the merchant's problem with that user more than the user's problem -- which is one potential stumbling block in user adoption.)

This doesn't alleviate the problem with nickel/dime scale micropayments, which is that users hate them with a passion unmatched by a thousand burning suns. That was true back when Clay Shirkey mentioned it in 2000 and is true today. The mental transaction cost makes every single microtransaction a significant barrier to conversion.

This is one reason aside from credit card fees why people who do micropayments successfully tend to use a dual currency model where the micropayment currency (bought for cash money) is as easy to spend as the currency which you can earn from ingame actions. (i.e. one-click no auth no confirm purchases, like buying something from the vendor in WoW.)