Gears did it, so why not?

Some arbitrary reason other than it being in excess to their capable workload. That's the long and short of it anyway. It's also an unfortunately common reason.

It was more of an optimistic "why not" than analytical. If I were to get analytical, compatibility between pc and console seems to be becoming one of Microsoft's bigger pushes in terms of customer appeal while Sony seems to lean more towards exclusives. I can't really support Sony for using that tactic though, as it feels more like tempting people with a piece of candy rather than offering anything of substance. Additionally Sony's movie production company has come up with some of the most dull productions of the past year. This group is also leading this year off with the emoji movie (unless the rumors of its cancelation is true), showing the use of profits made through their methods to further amplify this method. Even if they are two separate divisions, they both carry the name of Sony, and the decisions of both these groups feel more actively slimy when compared to Microsoft selling their word processor and computational tools separately from their pc hardware products because Sony baits their products to appeal to impulse purchases rather than trying to offer better overall quality.