The dyno is a very valuable tool. You can quickly and accurately measure gains (or losses) in the shop. I can play with cam timing, ignition/fuel mapping, do fuel testing, check driveline losses, and quickly and accurately diagnose problems on race or street bikes that would be impossible to do on the street, and without the time constraints you have at the track. Even with street bikes(or cars), it's a lot safer to take a 190mph vehicle up to redline on the dyno than it would be on the street. I would imagine I'd lose a lot of techs, and wouldn't be able to afford the insurance if we had to do the things we do on the dyno, on the street. Granted, I haven't figured out how to wheelie or do a stoppie on the dyno, but I'm not into that stuff anyway.