You will learn how to write profitable tests, in other terms
You'll learn how to reduce the cost of writing and maintaining tests while increasing their trustworthiness. This will boost the whole team's confidence and efficiency.
You will be able to choose the right tests to implement and how to implement them.
You will also learn how to leverage the benefits of Progressive TDD and Timeboxed TDD to change your code with confidence, and you will be able to decouple your tests from the tested code so you change the code structure without having to fix tests all the time..