The F1 is a single-seater. There isn’t enough room to accommodate a display as the WEC LMP1 or a Ferrari 488 GTE.
Take as an example the new the new Toyota TS050. It is a LMP1 made specific to be this way. I mean, the Carbon Fiber Monocoque has a design to have a plenty room to adapt the not only the screen and cameras but also the wing mirror (side view mirror). Put the mirror/screen on halo is going to interfere the driver vision, where is as part of the F1 Regulation (basic Federation Internationale de l’Automobile – FIA Regulation) the driver must have a 100% vision in front (ahead) of him/her.
However, a good question is: Does the Halo interfere the driver vision? If yes, it doesn’t obey this regulation?
Obs. The Formula 1 (F1) Channel had posted recently, a video showing the “Charles Leclerc And The New Halo Graphics | 2018 Azerbaijan Grand Prix”.
It is good for Television/YouTube viewer because it is an easy way to understand and appreciate how the telemetry works in F1. On the other side, it is an edited video and the point of view of the race driver, this kind of technology isn’t that simple to apply it.