This is not data collection, it's construction.
In this sense, the "model" is basically a TIN surface. The contractors can load that surface into their GPS-enabled equipment, then no matter where it is on the site, the equipment tells the operator how much up or down to get to grade. It's a dream for the big dirt movers who are throwing around 20 feet of cut/fill - way better than overlot stakes. Blade operators often mount GPS receivers on the ends of their blades for fine-tuning the grade. It can greatly decrease the amount of time required to grade large sites. Fancier equipment will combine GPS and lasers to allow an incredible amount of control, good enough that we've even paved runways to FAA standards with such a setup. (Although we only use that for the dirt subgrade and the asphalt base course... the top-level concrete is done with string lines.)
My interpretation was that the inexperienced Surveyor who was creating the model "for free" took two days and created an unusable model, whereas Thad was able to create a usable one in only two hours.