Earlier quoted context omitted.
In all fronts is the worst, except easy of build a cross-platform GUI (not necessarily native looking!). The thing is that is easy to get the basic widgets cross-platform but in the moment you need custom widgets or easy styling html/css just is easier. I wish exist a native renderer that could use a (saner, better) subset of html/css that fit the same use case, then let us use any better language for the logic. Prob…
JavaScript is NOT the first language to provide cross-platform GUI. Such toolkits are very old. Gtk, Qt, wxWidgets, and many others serve this functionality and have bindings across dozens of languages. There is no reason to use JavaScript just so you can get a "cross platform GUI".
Of course it's not.
> There is no reason to use JavaScript just so you can get a "cross platform GUI".
The main reason (imho) is that "JavaScript" (as you call it, but you should say "the web platform") is more future proof than "old toolkits".
Qt would be the best candidate for a "cross platform GUI", but you are relying on the [Qt company/nokia/whatever] for its continuation.
When you choose html/js you choose a standard used by virtually every single person with a computer nowadays. There is far less chance that html/js will be killed someday, like Microsoft killed WPF or like IBM made SWT an abandonware, because nobody is in that position and this whole World Wide Web thing rely on it.