With direct wifi, each monitor only needs to serve a single user, so the devices can be lower powered -- the broadcast only needs to serve ~a single desk. And they are centrally controlled by the IT department, so unlike a wifi router the in RF mad-max anarchy zone that is a modern apartment building, there shouldn't be concerns about noisy neighbors.
I'm not sure there's a point to all this -- the phone being used as a computer is probably going to be plugged in, so why not push everything through USB-C/thunderbolt nowadays? -- but it is almost certainly possible.
I agree the phone ought to be plugged in anyway. Even if it could survive a full day of being your workstation, you wouldn't want a half dead or worse battery at the end of your work day, and regularly draining a significant amount while stationary unnecessarily shortens the total battery lifespan. In addition, if docked into something with a bit of active cooling, the phone could perform better and once again preserve the battery.
For the second case, everyone only needs to broadcast with enough power to reach their device. Overlapping coverage areas are essentially a side effect.
I was thinking more along the lines of 1024x768. Non-power users. And if it was an Apple enviro, the display would be a computer, and the connection would be vnc or nx.