It's not the sound in itself that attracts people, it's the sense of speed that is created by the sound.

Its very difficult to judge the speed of a car just visually. A low rev megane r4 always looks slow because it sounds like a tractor, while a high revving s1600 car may be slower but looks a lot faster.

Also, the sound alows you to hear what a driver is doing. Is he keeping his foot down or is he lifting, is he breaking early or late. Is he driving clean or is he pushing.

Therefore if they actually want people to come and watch electric cars race, they will need a way to create sound that indicates how much throttle the drivers applies.