For racing leagues that focus more on technical advancement than on entertaining the crowd, their goals are:

• To make the cars as close to the same as possible, and focus only on driver performance. In computer games, the cars are exactly the same.
• To reduce expenses so more people can experience it, and so the best talent is attracted. In computer games, ongoing expenses are zero.
• To increase safety. In computer games, safety is guaranteed.

Of course, the real reason people enjoy racing, and enjoy watching racing, is because it's inherently risky. However, if you're focusing on technical advancement for a while, having a semi-realistic simulator will help you with that.