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.

Climbing harnesses are usually sitting harnesses that are more padded around the legs and back than work harnesses are.

The bigger thing, though, is that suspension trauma typically happens when you're purely hanging. The amount of time you can hang in a void in a work harness is way, way shorter than the amount of time you can bounce off a wall in a work harness, particularly if you're able to support much of your weight with your feet.

For climbers, the main worry would be hanging around if you're somehow incapacitated from a heart attack or having been knocked out somehow, because workers are a lot more likely to be suspended over a void than climbers.

That's like arguing a condom is less effective at preventing pregnancy than a trash bag, because the condom isn't as big.