There are things that a machine can do in a much better and reliable way than a human. Comparing lists of items is one of them (e.g: outputs of functions to be

There are things that a machine can do in a much better and reliable way than a human. Comparing lists of items is one of them (e.g: outputs of functions to be verified against expected results). And that's the entire point of using computers in the first place. Otherwise we can go back to pen and paper and process forms by hand. Does it make more sense for a human to do all the aspects of the testing by hand? Of course not. Nobody has budget for that. It's much better to automate as much testing as possible so testers can focus in higher level tasks. Like the risk assessment involved in marking a build as releasable. Then, unit testing encourages people to construct their software for verification. This software construction paradigm in itself is enough of a benefit even if unit tests are absent. Construction for verification diminishes coupling, and encourages developers to separate deterministic logic from logic depending on unreliable processes that require error handling. Doing this frequently trains you to become a better developer. Unreliable processes can be mocked and error handling can be tested in a deterministic way.