Comment by asalahli

I understood both this quote and the one I quoted above as OP arguing that automated testing will not save one from thinking about and fixing possible edge cases therefore automated testing has no value.

I agree with the first part but not the conclusion. My point is that with both manual and automated testing, you still needs to think. It's just that automated tests let you build an executable knowledge base of all the edge cases, errors, security issues etc. you've thought about in the past, and run them with every code change. Hence the value.