Likely due to copyright issues, the Technic 24 hour race car is modeled after typical Le Mans cars, but isn't a specific brand. Thus, users aren't going to get the same rush as building an iconic Porsche or Ferrari.
For perfectionists, there are dozens of stickers to try to apply perfectly to the pieces. For others, there's just a lot of stickers to deal which doesn't add too much additional fun to the building process. They feel more like a hassle.