As far as the OP mentioned about Travolta, if I recall some articles I saw, he had taken his son off of a few medicines several months ago and admitted that he was suffering from "severe" seizures at least once a week.
So, at least in his case, it was a bit more "If your kid starts to convulse after you take him off his meds, maybe that wasn't a bright idea." Granted, I suppose the religion was frowning on John's use of secular healing.
Overall, I suppose I have issues with religion as a whole, but philosophy ends up being useful, and taking various religious texts as philosophical texts are much more interesting. That being said, Scientology is based around science fiction texts, and I just simply can't find the philosophical importance of "The Courtship of Princess Leia" or "Heir to the Force."