This would allow for Electron-like frameworks that work on top of Gecko and SpiderMonkey instead of Chromium via CEF.
It would also be good for embedding webpages in desktop applications. As it stands, CEF is the go to for this along with some WebKit-based options like WPE.
Why is it that Webkit and Chromium technologies are actively used outside of the browser, but Gecko is not?
Let me just say this once:
Mozilla NEEDS THIS BADLY!!!