Why not just use the same rating system as the movies?

The two-part ESRB system was developed amid consumer demand for more detailed information than that which had previously been provided through other rating systems. Over 30 different content descriptors are used to indicate elements in a game that may have triggered a particular rating and/or may be of interest or concern, and are as helpful and important as the six age-based rating categories. As evidenced by both ESRB-commissioned consumer research as well as that conducted by the Federal Trade Commission (FTC), the vast majority of parents are now aware of and regularly using the ESRB ratings. In fact, in a study by the Kaiser Family Foundation about parental views of media rating systems for television, films, music and video games, 58% of parents said they consider the ESRB rating system to be “very useful” (the highest percentage among the various rating systems), and 91% found ESRB ratings to be either “very useful” or “somewhat useful.” Given these high levels of awareness, use and satisfaction with the ESRB rating system, it would not be sensible or practical to switch to a different system.