Use-case coverage is far more important than code coverage.
You can have 100% code coverage and still have your app break in prod.
Use cases can be encoded in end-to-end (E2E) tests, which will produce tests that are as close as possible to how an app will actually be used ✅
ALT Venn diagram showing code coverage in the left circle and use-case coverage in the right circle. The intersection is code that should be tested. The non-intersected area of the left circle says unused code. The non-intersected area of the right circle says missing code.