You can produce formally verified software with more expense than Java-Scripting. But is it software that does what we need it to do? Verification proves that

You can produce formally verified software with more expense than Java-Scripting. But is it software that does what we need it to do? Verification proves that software works according to its "spec". But is the spec "correct"? Writing NON-formally-verified software 10 x faster means you have a much better chance of figuring out how you should fix your spec.