its all about the racing and if the cars don't fill as realistic as they should then its not the sim for you.
Some people like the whole package not just the racing. It's fun to look at cars and get info on them, it's fun to tune them and paint them. F4 adds so much content to the franchise I feel like some one said that GT5 feels like a lacking video game. Even if the cars are photo realistic, once you got used to the graphics then except for doing endless events there's not much to do.