But having a talent in an art or being successful in a craft does not imply they have to be smart. Things like talents, good looks and circumstances play an important role. Especially in Hollywood. I do not believe Scientology celebrities are happier or personally more successful than most ordinary people, even though some of them might have gotten some level of publicly successful careers. To me it seems like they struggle with the same problems as everybody else.
Celebrities are under a great deal of stress, and often have a good deal of money to hand.
The expensive courses don't hurt them much, and Hubbard even said that celebrities should not be charged, only asked to donate what they wanted to donate. They might sample it just for the heck of it, and stay in. After all, they can easily afford to do so. There has also been speculations about the tax benefits for celebrities to stay as members of CoS, implying there might also be an economical side of this, in addition to the cult having huge files on the them with all their most personal confessions from auditing sessions. CoS has a history of using these files against defectors to either force them back or into silence.