No, they're not. Racers are concerned about weight above all else (well, except maybe horsepower). Spend some time in the pits and you'll see that those cars aren't arrow-straight, either. Of course, lots of them have graphics, contingency decals, what-have-you to distract the eye. You're also in a different context, so to speak... when you're looking at a racer, you're usually drooling over their engine/suspension/rolling stock/[insert racy bit here] rather than whether the car has ripples in the fenders.
It's a tough call, I ain't gonna lie. It's a trade-off. I've had some
really shabby-lookin' street cars with which one didn't want to necessarily tangle, including two 12-second dailies (back in the 1990s, a 12-second street car was pretty formidable). One was a '78 Trans Am to which a previous owner had
riveted the quarter panels (long story)
and my Dad backed into with his car--the day I got it. The other was a '72 Charger in which back-seat-passengers could pull the armrest/lower door panel outward and eject beer cans by firing them under the tires through the rust holes.

I'm pretty sure nobody wants to go home and tell Mama they got their ass handed to them by a rusty '69 Valiant with half the vinyl top missing, but I've got one with a solid-roller W2 340/4-speed that will present that opportunity. It's quicker than the either that Firechicken or Cha-Cha, but I haven't had it to the track yet. I love my sleepers, but I want my Challenger to be arrow-straight (and black) and to simply enjoy the car (and others' appreciation for it). Will it be fast? Fast enough. Will it run with the Valiant? No way. I have different priorities between the two.
Figure out where
your priorities lie and run with it. Hard to fault a guy for having a few ripples or waves when he showed you his taillights, and equally difficult to deride a fella with a drop-dead gorgeous car that runs high 15s. You're the only person you need to make happy, unless you're married (it's self-explanatory if you are

).
Just have fun. There's no other real reason to own one of these cars.