Dacs are awesome until you encounter a full rack with nothing but 2 and 4 meter dacs. They appeal very much to the lazy engineer, and a lazy engineer can turn them into a rats nest.
To be fair, the dedicated lazy engineer can make a rats nest out of any interconnect technology.
And they can block heat exhaustion
You.. but you put a ladder on the side. Rat's nest goes in the ladder, cover goes on top of the ladder. That way cables aren't blocking access to add/remove any U's.
You make sure all of the cabling has ends that can be pulled safely through the rat nests in the ladders (EG especially RJ45 cabling needs competent clip guards) and Bob's your uncle