A 4K version like this downsampled to 1080p will still look amazing because the source resolution is so high. I have a 75 inch LG UHD TV and a Cambridge Audio UHD media player (capable of reading this file off a USB, I might add), and 4K discs hardly look that different than 1080p to the naked eye in terms of perceiving pure resolution from a normal viewing distance. The best part of commercial UHD technology, IMO, is the expanded color gamut confered by either HDR or Dolby Vision technology, which these projects have not and cannot take advantage at present.
In my experience, there’s a barely perceptible difference in resolution between 2160p and 1080p (I have 30+ UHD 4K movies and have compared several with the 1080p releases); the most important factor is a high quality and high res source scan. That’s what I’m paying for when I buy 4K discs.
That’s because most UHD Blu-Ray releases are really 2k sources upscaled to 2160p. Compare the 1080p Blu-Ray to the UHD Blu-ray of something like Blue Planet 2 and you can really tell the difference. Plus you don;t really need a UHD media player. The LG UHDTV is able to playback the 4k77 file, and other UHD files, just fine via a usb stick/ external usb drive ( I have the 70inch HDR LG TV).