Holy shit you know absolutely nothing. I've been rock climbing for more than a decade. You can sit in a climbing harness for hours and hours. It's not the most comfortable thing. But I've spent multiple hours sitting in harness's countless times in my life. I can't believe I'm even having this conversation with someone who knows absolutely nothing about what they are talking about.

For the sake of this photo they are tied into ropes coming up from below but they also have an anchor point above in the background and most likely a point directly on the ledge they are on. They will be tied into very short dynamic ropes for the majority of their time up there making it very difficult to fall more than a couple feet.