I appreciate your points, but I'd argue that not everyone is good at or enjoys trying to figure things out while a bunch of people watch, with or without commenting. I also do not enjoy and am not good at sitting there watching someone else figure something out. And handing someone the solution often is counterproductive or not appreciated.

I also find that when I go back after 6 months or a year and the original programmer has forgotten or left the team, the review comments are VERY valuable to have when you're wondering why the code in front of you is written that way.