Several take aways from this decision and multiple ways to look at it.

The first being that Joe most likely isn't lucid currently and they don't know if they can get him back in time. We all know there's a problem with his mind and it's easy to notice if you've watched anytime he's spoken somewhere. Virtual is the easiest way to make it seem like he's there, but it's all been pre-recorded and played for the general public. Example of this is go watch the dnc speech again. No way that's live.

Secondly, they want the power to mute POTUS while biden is speaking. Yes, microphones can be turned off, but standing next to a guy calling your shit out will make you say dumb things while you're the only one being heard. So, how to get around that? You mute the guy so no one can hear him. It also makes it easier to interject things from a pre-recording and easier to hide a teleprompter. They also don't want the same calling out and talking over with truth that has now happened twice to the shit candidates.

Basically, it's a terrible idea that they thought would work to pull the wool over the eyes of the people so that they can try to salvage what little they have left.