With the per eye resolution for your entire field of view being only slightly more than the resolution of the MacBook's main screen, replacing 4 additional screens seems lofty. I mean yeah, there is plenty of visual space to place all of the screens... but that's a heck of a DPI downgrade before we even get to unused visual space, stretching/warp of placing flat-rendered screens in positions across a perspective render, and the optics. There is also the whole matter of streaming that much low-latency screen over Wi-Fi from the MacBook, which is why I think it's limited to 1x 4k screen right now (per the video).

Virtual screens is probably #1 on my VR/AR productivity list but, having tried so many prior solutions, I just couldn't believe them no matter how many times they repeated "crisp text" when talking about it. I'd love to see it and be so wrong... but the specs don't have me holding my breath. Maybe if it had double the resolution per eye it'd start to be something worth considering.