I'd argue on the contrary, having the business domain in the type system allows the compiler to help you ensure the changes are made correctly instead of relyin

I'd argue on the contrary, having the business domain in the type system allows the compiler to help you ensure the changes are made correctly instead of relying purely on tests (which are still valuable, but I'll take guarantees where I can get them). The type system also makes it easy to reduce the state space of the program. For example, if a method takes an int as a parameter you have a pretty large state space. But if it takes a strongly typed enum which can only be of 3 values, now you have restricted the surface area for which you have to test. If you exploit the type system to this effect it is very powerful.