Not sure why anyone interested in writing a cross-platform application would even think of Objective-C. You must be an OSX user.
Just as one example, Komanda could've been done with Python and any of the variety of cross-platform GUI toolkits available for that language. It would run everywhere, faster, using native widgets, and in a language designed for the desktop.
If I am lazy and I write in Python 2.7 are you sure you can run my code on your Python 3.4 branch without using 2to3 tool?
Are you sure all the GUI library will work on every popular platform (Windows XP, Vista, 7, 8, Mac OSX 10.6+, Ubuntu 10-14, Arch, never mind all XDE, KDE, GNOME, XFCE, etc dealing with native widget???) I really don't think the development experience would be as seamlessly as you think.
Could QT be made to look as pretty? QT based apps are notoriously hard to work with on OSX, they never quite manage to fit in at all. That said I can't get this one to function at all, so it's a moot point as far as usability goes.
Replicating web-style prettified UIs seems to be one of the major goals of QML. In any case, if your alternative is an HTML/CSS/JS/Node application, I don't think replicating native look and feel is really that likely to be a sticking point.
Perhaps not, but he didn't say that. There is more than just language at play in this scenario. Will a native widget, initiated by Python, out perform JS/CSS/Node-Webkit ... maybe.
The OP saying the app will run faster is not refuted even if NodeJS runs some things faster than Python.
Just as one example, Komanda could've been done with Python and any of the variety of cross-platform GUI toolkits available for that language. It would run everywhere, faster, using native widgets, and in a language designed for the desktop.