Mathfox:
Private jet, the issue is one of competence versus certification; I rather have a competent uncertified pilot in the driver seat than an incompetent certified one.
So you would be happy to wake up after an operation, and find out that your surgeon was actually a bricklayer - but that they were 'good with their hands'?
I think you misunderstand why we have ATPL courses and licences that demonstrate we have taken those courses.