The debugger is one of the key features of Wolfram Workbench. One of the prime benefits is the ability to use different breakpoint types and watch expressions to study your code as it runs, so that you can detect and fix any problems.
The Workbench profiler allows you to see details of the execution of your Mathematica functions. Seeing the number of evaluations and time spent on parts of your code can highlight areas that will yield the highest return for optimization efforts. This report shows that much of the time was spent on vector multiplication; as this is a fast operation, we can see that the execution time for this function is optimized.