Hi, Mike. Thanks so much for giving PureCloud for Chrome a spin and for your questions.
It seems like the main one that's left is, "Why did I need to download two thing?"
The answer is basically the capabilities that Google provides for Chrome apps versus the capabilities that Google provides for Chrome extensions. We used an app because that gave us "always on top" functionality. We used an extension because that gave us the click-to-dial/make call functionality, and it also gave us the ability to have an options section, which folks use to point to the correct region for their application.
Does that help? Let us know. And, thanks again!