Bitcoin seems ideally suited to the purchase of digital goods - apps, music, e-books etc.
According to the top answer in this Quora question http://www.quora.com/How-much-does-Apple-pay-on-credit-card-transactions-in-the-appstore
then Apple could be paying up to 15¢ on a 99¢ itunes purchase to the credit card companies. I assume Google (and Amazon with their market) pay something similar. Using bitcoin cuts out this credit card fee, think about how much money that adds up to.
I don't expect Apple, Google or Amazon to start accepting bitcoin as a payment mechanism anytime soon but I may be wrong but I think anyone can set up an Android app store. Without the credit card fee there is enough room for this store operator to pay more to the app developer, reduce the price to the app buyer and have a bit left over for themselves.
Another benefit could be being able to offer paid apps in more countries. I read somewhere that paid apps on the Google android store are only available in select countries where Google checkout operates (my info may be out of date). Perhaps some forum members can confirm if paid Android apps are not available in their country. Obviously being able to offer paid apps in countries where they are not yet available is a win for everyone - developer, consumer and the store operator.
All we need is for someone to build it.