I'm not convinced over the effectiveness of polishing a clear coat of paint.
Polishing the actual metal makes sense but the scale of improvement caused by polishing something already smooth and shiny seems too small to be worth the effort.
You would be very surprised at what difference it can make, maybe not so much on a brand new vehicle but on something that has had its fair share of weathering, use and washes it can make a big impact.
For instance the below picture is of a section of a bonnet that i had cleansed, de-contaminated, clayed and then corrected using some meguiars compound and a DA, this was only the first stage of the correction. I had masked off the section to get a clean line to show the difference, hopefully you will see that the improvement is fairly obvious.
Now if you keep in mind that every one of those little scratches detracts from the shine and finish of your car it can make a BIG difference once you have corrected a significant amount of them.