How is only scanning the outside better than checking the inside?

Sure, visual imaging is cheap and high-definition, but it's also a pretty low value product. People can already see the outside of their body. Instead of a fancy full-body visual scanner just give them a pamphlet which things are normal, which are abnormal but harmless and which need a doctor visit.

Seeing the inside of your body on the other hand opens up a lot of things you previously couldn't see. We have to be careful not to overreact and try to "fix" all bodies to fit the image printed in the textbook. But the potential to do real good is huge