Court trials can be pretty tense, and judicial officers expect you to substantiate your every claim. Attorneys need to be organized and prepared. The last thing you want is the jury or the arbitrator to focus on your failing A/V equipment.
Your presentation could fail to load during the trial, or the sound quality could be inaudible. Also, you could ruin the prospects of winning by displaying exhibits out of sync with your arguments.
Hot seat operators are behind-the-scenes heroes. All focus goes to the trial attorney while the technician controls all the visuals.