No, *testing* your code is what’s important. Whether it’s manually or unit, before or after, isn’t important. Any decent blackbox tester working from a functional spec is going to beat the pants off “unit tests” or TDD. And we usually have multiple blackbox testers, or rather we used to. Microsoft doesn’t have them anymore because that moron Nadella fired them all.
And it’s fewer bugs. Countable. Less water, fewer people.