A World class server told me something very different. And what he said was more in line with my general experience. But you are right of course - good serves are good serves and can give good players problems.
I am not saying that one should never serve long or that one should not throw in fast long serves or even use them a lot if the opponent struggles with them. I am saying that most plays will play such balls with their training and without fear and it is often the one thing that most players have been doing long and well enough to act without thinking.
When I used to serve long as a lower rated player, I had this view that oh, the opponent was due to miss one. What you realize is that as players get better, they let the ball come deeper and deeper and they will rarely loop the ball long - they will usually put it on the table and if they feel they can see the ball clearly, they will loop kill it. Their footwork allows them to get anywhere so you can hardly serve faster than they can respond. That's why I try to warn people that above a certain level, you have stop playing critical points as if you expect the opponent to miss or give you a weak ball. Most people who serve long as a surprise tactic are doing that.