[kibwen]

> still asking the question?

Yes, because the question isn't "how is this useful", it's "how is it in Mozilla's best interest to invest in this?" Mozilla came up with XUL because they wanted a cross-platform way to develop a large graphical application, and given that they're an open source organization they figured they might as well try to popularize the framework to hopefully get some volunteer contributions to the codebase. But XUL was never an end, only a means to an end, and the technology itself no longer has any strategic advantage.

As for "failing to execute" on taking over the world of desktop apps with XUL, I don't think Mozilla will lose any sleep over it. The secret sauce to Electron isn't Chromium, it's Node.js. We can say that Mozilla failed to execute the opportunity to popularize server-side Javascript first... but that's Rhino was for, and really, nobody in 2005 would have foreseen that developers would eventually want to write their backends in Javascript. :P