You knowing the codebase and operating a node is akin to a race car driver also being their own mechanic/tuner. They develop intuition what is going on with the car, just by driving it. I have no idea how many witnesses fit into that category, but there is no doubt in my mind they are essential.
I like the analogy! But I would take it one step further -- it's a bus or a plane, and the average users are along for the ride. Since your fate is beholden to them not crashing, you probably want the best in the pilot seat, and the best making sure things don't fall apart.