[montroser]

It matters for at least a few reasons:

- Depending on the nature of your application, it may be very important to be able to audit the business logic and intended behavior. For compliance reasons, for operational reasons, for moral/ethical reasons -- you very well might want to affirm what the code is actually trying to do.

- A coding agent may get very creative in order to write code that passes a tightly-defined unit test. It may come up with approaches that technically pass, but work against the overall intention of the app in the first place. This becomes an arms race rather than a productive collaboration, where the agent's increasing creativity has to be matched by a sprawling test suite.

- Eventually, inevitably, business requirements will change, and the blob will need to evolve. It will be much easier for an agent or a human alike to understand how to safely make the change, if the existing implementation is transparent and understandable.