Yeah, the rewind feature is awesome. If it didn't exist, it would just be like every other racing game. It really lets you try out some interesting and risky moves, though. In the past, if I wasn't 100% sure I could overtake a car on a turn, I wouldn't gun for it. Now, I can try out different strategies to get ahead, if one fails then I can just try a different one.
It also removes the inevitable frustrations of these games where you've got a good lead until the end, but mess up the final turn and watch in horror as your opponents pass by you and the last 10 minutes were for nothing. Not anymore! Ain't no one taking my victory from me!