$$$$, my nikka...
NASCAR has seen attendance fall off at tracks across the country. A lot of the traditional fans have been staying away since they feel that NASCAR is abandoning their roots (read: rednecks) and selling out for dough. Like it or not, Danica is popular and will move merchandise. The only one who might trump her in popularity is Earnhardt Jr. Look at Jimmie Johnson; the nikka has won stayed winning the Sprint Cup, and outside of his Lowe's commercials, nobody really knows who he is, aside from NASCAR enthusiasts. Danica is a crossover star, which always means $$$$. An average broad who has no idea about car racing might be inclined to buy something NASCAR related because Danica pushes it.
Should she be in the position that she's in? I don't think so. She needed another year or two of seasoning in Nationwide before jumping to the big show. Like Chris Rock said, "I'm not saying they shoulda did it... But I understand"