I see this as a push for a larger goal for Google -- the one thing Google has been weak on is since in most customer interactions everything is free, they have a lot of work to do in building up their payment ecosystem anf getting people used to paying Google for things.
Google checkout has been seen as a failure, but they continue slowly increasing its footprint for their use, which tells us how strategic they see it. How important Itunes has been to Ipod/Iphone success is unquestionable, the payment system was already set up.
In part at least, I have to think that Google moving Android handsets to Gcheckout is motivated by the desire to push checkout. It's really no different than paypal, once you have one its quite easy to use. Often said that a downside of google app store is you have to use google checkout, but that certainly is not a downside to Google, it's vital, and once the nuisance is overcome their ecosystem becomes much stronger. It was no less a nuisance that Itunes did not use Paypal back in the day.
Looking down the road, towards youtube subscriptions they've talked about, a possible ebook store they've talked about, whatever they bolt into the chrome os ecosystem, a strong checkout is vital for them. I think they missed the boat on lala.com, as that would have meshed perfectly with both their cloud strategy a la chrome os, and given them another way to strongly push checkout to casual users. That was a very important purchase by Apple.
