You can get a constant data feed and play quickly...data does not influence number of waggles, prompt club selection (if you truly know and trust your numbers), hip shimmies, head cocks and other idiosyncracies that slow golfers to a crawl. Golfers who shoot high numbers can play quickly, while scratch and better golfers can be slow as constipation.
So many have touched on it, yet I will reiterate...when "amateurs" attempt to do things that "professionals" do, the former are bound to screw up. When the "professionals" do it poorly (faster play) to begin with, the "amateurs" will compound the error, adding additional time and sequences to the process.
Finally, consider attitude. Many golfers feel that they have earned their time on the course and, by gum, if they want to take extra time on, say, every shot, tough tittles. They've paid and earned the slot.
How do you combat that, especially on a public course?