I dont see how it grows the IP by making it exclusive to a smaller audience (not wanting to disdain Xbox owners at all, just analisyng the reasoning presented).
Of course, for Microsoft it makes perfect sense. For Squeenix, as much as they beat around the bush... it was about the money. That is all.
I think they havent done well by the IP, or by their contract with MS with this early announcement of other versions, or either by the PS fans by releasing it a year later. But whatever... just say its cause of the money, cause we all know it was.