Right, the thing I find it does really often is to replicate policy through more than one mechanism. For example, this week, I was working on a const structure in rust that i needed to be able to serialize in a const context. It implemented the calculation of the serialized string length independently from the serialization string. It would certainly have worked, and probably for a long time, but it opened a potential bug route that I never would have created. This was on a single module.