And a dyno tune is done once. If you decide a couple months from now that you want to do something a little different to your car, you have to pay to have it re-tuned. Not to mention that your car runs totally different in the winter than in the summer.
With my tuner, I have multiple tunes for my car. I have daily driver tunes for mileage, summer tunes, winter tunes, aggressive street tunes for Friday night cruising, and all out race tunes. And if I change a mod on my car, I can easily re-tune it and have it running perfect again, and not pay anything extra.
Just my $.03 (damn inflation).