There has been a lot of debate about whether or not trying new aero packages in the middle of the season is a good thing. I applaud NASCAR for recognizing that their current product was not what they hoped it would be and, instead of waiting until the end of the year to do something about it (and, maybe missing again), trying to fix it now. Or at least, finding out what does or doesn't work.
What NASCAR has realized is that, no matter how many cars you take to a test session, they will not run like they do in real competition. The move we saw Kyle Busch make in the Xfinity race at Indianapolis for instance, would he have tried that during a test session. Or how about Brad Keselowski sticking his nose between Jeff Gordon and Jimmie Johnson at Texas last fall; you can bet, he wouldn't have tried that in a test session.
Test sessions are simple examples of risk versus reward. There is no reward for putting yourself and your equipment at risk, so why push the envelope.
So, what we have instead are points paying test sessions. We've seen two at Kentucky and Indy and will see two more at Michigan and Darlington. We are getting to see how these cars react under real race conditions; risk and all.
And, as scientists will tell you, even failure is a success. You learn what doesn't work.