A real code coverage metric has a useful purpose If the value is too low, then the set of unit tests are not going to be as helpful for unit testing as they should be. As a manager, the actual value isn't as important as the relative value, Low scores can indicate poor tests or overly complex T-SQL. It can also indicate T-SQL with many error paths that are not being tested.

A code coverage metric is also useful in the context of DevOps and automated testing. If the code coverage metric drops on a new release, its probably an indication that there is new, untested code. 

A code coverage metric is one tool. Fixating on the value to be achieved provides little benefit. Focusing on why it varies from the expected for newly introduced artifacts and for regression testing can catch problems before they occur. A high value won't guarantee everything is functionally correct.