I wore them for many years, on ground or aloft, as everyone else I worked with. Saw pants are much better, but chaps aren’t too cumbersome and even offer benefit of extra padding
I've worn my chaps while climbing a few times. They were OK, but as suggested above they do get caught on stuff. Not horribly, but at the nuisance level. Partly because of the trees I was climbing. I've been up some boxelders that would have been horrible with chaps. Pants, though, might be pretty comfortable. Especially for the padding and warmth in the winter.
A related question is eye protection. I have a full face mesh shield on my helmet that is a real nuisance when it's flipped up. Catches on everything. Wearing it down when I climb cuts my vision pretty severely, especially in the low light at this time of year (Wisconsin--sunset about 4 pm). I wear glasses that give minimal protection, but often not enough. Suggestions?