a good polish can do more than just clean. It can repair some minor scratches as well..
Have you ever touch a new car in the dealership? The car is very smooth and shine. And when you go home and touch your car, it will be rough. Its the advantage of polish. Everyday driving, stone chips, mud, bird poos.. will be all over the car.. and polish will be able to removes those things. Regular car wash cannot do it!
Wax is the protection of your polish. It like putting a wrap outside your car. It protects from minor chemical that can harm your car.
Have fuN!