To be fair, the flattering comparison table should come with things like "Natively supported by the OS" or "Large community support", for which xonsh would obviously be at a disadvantage compared to other shells.
But this all depends on the OS; OS X only gives you an old version of BASH as the default shell and OpenBSD (and possibly other BSDs) require installing BASH through the ports tree.
Its there for humor, not a serious comparison tool. And I can respect that.