Back when my wife did environmental work, she found that the details were sometimes useful. There was one time in Waltham where Digsafe improperly marked the location of the gas main and the driller center punched the main. Then there was a large, long-term project on a road with a lot of traffic and a 45 mph speed limit. On that project, their detail officer stopped traffic to allow them to make the left turn into the site, and to allow the construction trucks to get into and out of the site.
In general, though, I think details are an unnecessary expense. I had to hire a detail officer at $450 for less than 1/2 a day simply to take a tree down at my house.