Due to the fact you have to ramp up the per-move difficulty much faster on a bouldering problem as the grade increases, the chance per injury on any given move is much higher (e.g. if you chopped a bouldering-sized section out of a 5.12a, it wouldn't be that hard of a problem, but having to do 3-4x such problems in a row is much more grueling). The types of injury one gets from such intense exertion will impact one's ability to type too (e.g. finger pulley injuries, elbow injuries either in terms of the rotation of one's wrist or spraining if one does the typical "fall off the wall and put your hands behind you" thing I've seen on the bouldering wall).
> Can be done solo.
I'd argue this is a bug, not a feature. I've made so many great friends at the climbing gym by just asking people on the autobelays if they want to pair up for roped climbing (or joining an odd-numbered group of people to even it out), yet I see so many boulderers just silently do their thing with their airpods in.
For software engineers who don't get a lot of reps in social situations in the nature of our jobs, this is a very easy venue to learn to meet new people in a low-stakes situation.