At the same time, though, you know it's there, even at subconscious level knowing you can always 'undo' when you screw things, makes you a lot more reckless, makes you pay a lot less attention than you would otherwise.
Trying to get a clean lap on the leaderboard is a completely different experience.
Personally, with AI trying to ram you out of the track on the last corner, i welcome being able to rewind, because i really don't have much time to restart races (yes, what about restart then ? should it be removed too ?).
It does take a lot of the excitement away, and a lot of fun as a consequence, though.
The principle of fun in a game is the risk / reward ratio, and rewind takes most of the risk away. Being able to rewind is a bit like playing an old school shoot em up with infinite lives.
But that's what games have become; games today are not just for people with a lot of spare time on their hands. That's the price we had to pay for games to become a socially acceptable hobby.
Having said that, T10 could just give you the option to disable rewind and get a huge boost in credits for doing so. Such an easy fix.