I think if you spent a day on the dyno, you'd change your mind. It's not different than a flow bench or any other tool.
It can show you things you'll never learn at the track. You can isolate things on the dyno you can't on the track. Most guys now can measure many things with onboard data logging, but you still add way too many variable to the equation.
I've seen many 600 HP engines ET like 500 HP engines and the dyno takes the blame when the chassis or converter or gear or all of them are the issue.
