One of the best things about sports is when an athlete attempts something that has seldom been done, especially when it involves a sport different from what they are known for. 

Yes, motorsports could include both the IndyCar Series and NASCAR's Cup Series, but at the end of the day, the cars are built differently and handle differently. It is rare that the calendars line up between the series, at least with prominent events. The one day a year that they do is on Memorial Day Weekend.