There's almost nothing that you can do with Cordova that you couldn't do with mobile Chrome apps, since, under the hood, they are Cordova apps.

In fact, the plugins themselves have all been available for some time on the Cordova plugin registry (I think Andrew announced this at PhoneGapDay in Amsterdam last year), and you can use them on standalone Cordova projects.

Much of this project is about getting Chrome packaged apps to run as Cordova apps -- that is, single-page apps, with a manifest file, background scripts, and the chrome.* APIs. The goal is that you could take an existing packaged app, build it with this tool, and have an Android and an iOS version running in a couple of minutes. (There are obviously a lot of caveats in that statement; mobile devices are different from desktop in a lot of ways)

There's no intention of being "better" than Cordova -- We've been a big part of the team that has been building Cordova for the last couple of years. If anything, it's a testament to how powerful the Cordova platform is, that we've been able to build this framework on top of it.

This is just Cordova with Chrome App APIs. It doesn't run on top of Chrome or anything like that. So the only difference is you can now have API compatibility between your real Chrome App, and your "fake" Cordova-powered "Chrome App"

Unless you're using Android KitKat, then the web view is actually chrome.

Not sure, but maybe there's something in the noted upcoming 'toolchain' that might be interesting? Personally, I'm not holding my breath.

Nothing, they just aliased existing PhoneGap APIs to the chrome.* equivalents.