Easier, fast to type, cool, etc... I don't know but in Brazilian it fells like agreat word while I have a hell of trouble to pronunciate Xbox One.
I never said that in a offensive way or even bashing... I think MS choose this name instead Xbox One it will be way better in a marketing point.
I don't think Microsoft chose it? And isn't XOne easier? Looks cooler too and the Xbox 360 wasn't called XB360 either, it was X360. Sure a little off-topic but hey important nontheless haha.