Re: Serious Question
It's more about user experience, probably. I think we all know that browsers and OS are becoming ever more linked, to the point that in some cases (ChromeOS) they actually are the same thing. MS had Windows Active Desktop once upon a time which was an early step down this road (wow - do they look prescient now!).
Anyway, with OS and browser becoming ever more entwined, IE10 is gradually becoming an extension of the OS. And on ARM that is even more so given that WOA lacks the combo-Win32 and Metro API access that the desktop version does. So basically, either MS give up the whole sandboxed, more limited API model they planned to use in WOA for installable applications, or they cast themselves on the other side of it and say that nobody including themselves, gets to have a closely integrated OS-browser model. At which point they get pummelled by groups like Google and Apple who have no objection to doing this sort of close integration.
It is bad that there is less choice. But at the same time, I can see why Windows, on a tightly controlled device like a tablet (remember, we're only talking about Windows on Arm, here) want to prevent installable Apps that spawn multiple processes at will and directly fiddle with the memory. Essentially, they trust themselves to do that, but not to let any old random App writer to have that sort of power. Are Firefox "any old random App writer"? Well, if not, how do you say who is?