A service worker is a script that your browser runs in the background, separate from a web page, opening the door to features that don't need a web page or user interaction.
Also, what is the current status to be able to do client http requests? I have found a way around this using bidirectional
postMessages and a
Visualforce Page embedded as an iframe, then built a listener component to handle the back and forth of request and response.
I also found some issues with the framework around using the
set attribute to render another body inside that component, the component will not rerender if the parent objects get changed.
If you look at the aura git repo, there are so many cool components, which salesforce have not even exposed yet.