Sure. - sounds reasonable.
Slytherin!
Yes, a magic ray that hits you for a few minutes a day can reverse a terminal disease. Sure. Sounds reasonable. Thing is, radiation therapy is effective in fighting cancer. It's been refined through a lot of false leads and a lot of tests and trials.
I'm not buying the hype for the Alzheimer's helmet, but it's worth pursuing. I won't accept it uncritically, but I won't reject it out of hand. If you told me that there was some magic substance derived from tree bark that could relieve headache and heart attacks, I'd think you were nuts. And yet we have aspirin.