Ok ... I'll try to put it simply, although there are many other reasons why Sony may want to do this: Scalebound has been delayed until 2017. Sony will already be considering what their possible line up will be for 2017. Now they know MS has Scalebound and could release earlier in the year, something they haven't been able to do for a while. This means Sony now have to consider what to put up against it, if only to have content available. With VR games already made it seems to me the perfect solution to fill any holes in their portfolio, rather like remasters have this year. It's just another option.
It wouldn't devalue VR because VR is a completely different experience and it isn't going to be exlusives that sell the product, it's going to be THAT experience. Perhaps once VR is established, exlusives will matter as far as competing with Oculus (or any other VR headset) but it's not going to count for much for the first year and a half.
i think 2016 proves that Sony will have content available whether they have direct control over it or not. X1 games being delayed is a non-issue for Sony at this point. It just means they have better opportunity for success in 2016 which is really all they need. MS having a strong 2017 is almost an irrelevant point at this stage of the gen. Good for X1 owners of course.
And I think ppl are overselling the EXPERIENCE part of VR if you think that alone is going to sell a potetnailly $400 product. VR is an awesome experience but I aint throwing that kind of money at a device that is going to have tons of experiences that can be played without it.
the VR experience + games that need a VR device is what it going to sell an additional peripheral on top of having a PS4. You need a PS4 for PSVR, having VR games become compatible for non-VR users is not going to make a noticeable bump in hardware sales.