It would obviously be an upscaled resolution in games. 4k is for the screen door effect.
4k is necessary for readable text, ability to watch HD movies and using virtual monitors. Currently the resolution is too low for any of these, as in it works but not good enough for being practical.
Yeah, I'm pretty sure I read that the screen door effect were even less visible in the Sony Morpheus prototype, even though it had less resolution than the Crescent Bay prototype.
I think the general consensus is that it helps, but also other ticks help like the diamond shaped pixels in the HTC Vive.
Current resolution still not works well with viewing virtual screens e.g. movies, virtual desktops and text.
I think this is much more important as it increases practicality of the device.
Forget graphics card support, HDMI 2.0 cannot even support 4K at higher than 60FPS. Considering how important pushing higher frame rates is to reducing latency, that seems like a nonstarter.
GPUs will continue improving. For now, upscaling would still be very good, especially for screen door effect. Though, I have a gtx980 that is just fine pushing incredible frame rates at 4k.
