Being able to swap out the phone dialer with a SIP client means my Droid can make and receive calls when I'm on Wifi in Europe, where it's CDMA network doesn't exist.
I'll give this one partial credit: there's no doubt that it's useful. I don't think, however that it meets the parameters of my original question. I think the dialer is part of the open-source Android distribution, and it isn't one of "the Google apps" I had in mind.
More importantly, this is a replacement done by the user. Being able to customize your own OS is always (in principle) a benefit. I'm talking about things like AT&T hiding Google Navigation on some of its Android phones to encourage the use of its own paid navigation app.
Fair point; I think a lot of the US carrier customisations have been detrimental. What I was getting at in the original post was that we're going to see a lot of things running Android that we didn't expect, and that aren't on Google's roadmap. Avoiding the BizDev tax by replacing some of the Google proprietary apps will come too.
For all I know, this is already going on in Asia.
More importantly, this is a replacement done by the user. Being able to customize your own OS is always (in principle) a benefit. I'm talking about things like AT&T hiding Google Navigation on some of its Android phones to encourage the use of its own paid navigation app.