The biggest reason I love TDD as a developer, is that is effectively forces you to decouple your code. Otherwise it is really hard to test a single unit of code. If you are writing complicated mocks, stubs, and fakes; you probably need to decouple your code further. In the near future, I predict that TDD will not slow development when using AI from written requirements to start your tests.
For all the other reasons, you can read up on the standard advantages/disadvantages of TDD written by someone smarter and more articulate than myself.
Let's show an example: