That's because devs wont have access to larger discs (because the discs still need to be compatible with base). The device will still play UHD Blu-rays, it's just not information relevant to devs so they didn't bother include it in the documentation. Not that actually have any information but just think about for a sec and it makes sense. Sony isn't going to make a 4k focused device that only outputs 4k for Netflix and not their most obvious source of 4k content.
Same would be true for integrating the VR breakout box, though I'm less sure Sony would actually bother (PSVR is going to be sold with the box either way, so what's the point? Selling an SKU without the breakout box would be one too many and would create costumer confusion.)