I believe in them. But unit tests are useless around useless humans. And there’s lots of those. A fine example is that time I wrote a test suite for a domain specific language parser. Someone wanted to break the language so they deleted the tests. New stuff was added without tests.

They confidently broke everything historically and looking forward. Then blamed it on me because it was my test suite that didn’t catch it. The language should not have been broken.

Everything only works if you understand what you are doing so every argument should be posed as both sides.