I'm not a tech, but I feel like I have to throw in my $0.02. A Mercedes is just a car, and cars are just like any other machine. I consider cars deterministic machines with input and output. Everything in a car is causally related and at any given time, any car might be in a particular state. Essentially, the tech's job is to solve for the unknown in the machine if the output isn't correct. My interpretation of Benzmac's recommendation was that if these three things are working, then a large amount of the puzzle is solved. This leaves us with the perhaps only half of the possible problems.
If you haven't realized it yet, I'm trying to justify Benzmac's response in my eyes. In saying that this symptom is caused by three major components, he's trying to provide a "most plausible" scenario. It's a little like hands on Mathematics. Your Algebra teacher is going to look at the answer you give first, if it's wrong, then quite possibly the parentheses are in the wrong spot or you misplaced a minus sign. "Fixing" either one of these might be just what the doctor ordered.
Another angle I would like to explore is that the things Benzmac said might have caused the problem, crank sensor, coil, fuel pump relay, are givens. Okay, perhaps not the fuel pump relay, but the coil. In this case the coil is no more nor less important than like Gilly said, having gas in the tank. It's axiomatic just like you have to plug your TV into the wall for it to work, or if we want to pick on a component, we should make sure the plug is properly wired first.
It's obvious that just like there are different kinds of people in this world, there are different kinds of techs who approach problem solving differently. I'm a chef, a tech of a different sort. I see people with food problems both on and off the job. When people ask me why their stuff doesn't work I don't even ask them what they did, I just tell them what needs to be done right first. Make sure you have skillet (battery) is hot (charged). Some people can't do that, they have to go through the whole process before making a diagnosis, which I can't.
Kuan (definitely not a tech)