This brings back memories. Although some best forgot.
In summary you go to the effort of drilling a hole, but instead of placing a bolt you bash in an filed down coach bolt and the climber has a bunch of pseudo hangers in his/her chalk bag. It a bit weird, like leaving half the bolting job to a succession of climbers who inevitably have hangers that don’t fit properly.
In addition, years down the line the coach bolt has rusted and half removed itself, your biners don't fit the carrot/hanger combo, you drop the hanger while trying to fiddle it on, or you knock the hanger while trying to fiddle the quick draw on, or all of the above. You often resort to placing a wire over the carrot because you are tired of fiddly hangers on or have already dropped them all.
To add to the excitement, the carrots are often at full reach or awkward angles so this is a very plausible scenario:
At the crux, locked off on some crimp, you try to fiddle on a hanger at full stretch. It won’t fit so after some cursing, you put it back in your chalk bag and try find a different style hanger that may fit. You either grab the exact same hanger you just put back in you chalk, or another one that doesn’t fit. You cuss some more, and decide to put that one in your mouth to remove it from the pot. You get another hanger that doesn’t fit, swear again – dropping the one in your mouth. F&^k! Now you are pumped and pissed off. You clip the current hanger to the biners of one of your draws. The forth hanger eventually fits, but now you are really pumped. You grab a draw, but that is the one with the third hanger on it. Sh*t! Put that back on your harness, grab another draw but the biner doesn’t fit through the carrot/hanger combo. FFS! Now you one arm is really cramping, and you have had enough of this BS. You frantically rummage across your harness to find a draw with a different shape biner. With fingers nearly pealing of the crimp, you shakily try to get the correct draw into the hanger, but just when the trauma is almost over you dislodge the hanger and you too peel off the wall, dropping the draw.
Unfortunately the last carrot you clipped was rusted and mostly pointing down, so it just pulls out the wall. Since you have now had a sizeable fall, you also ding you ankle slightly. Thus the score is that you have blown the send, lost two hangers and a draw, your foot is saw, your mouth is covered in chalk and you may have had a partial pulley tear from excessive hanging on the crimp. Furthermore your options are now to do it all again but with a much longer run out, or bail which means loosing even more gear.
All of which could be avoided with standard bolt…
One life, one body. Use them well.