Well , that all depends on how deep they are.
For example , some scratches may look deep, but very much could just be just a fine scratch , or even paint transfer , these will only need machine polishing out. 

On the other hand some scratches could be very deep . These deeper scratches may need a bit more attention, the use of : paint touch up , sanding and advanced polishing techniques to reduce or remove the scratches from the paint. 

The goal ,with the deeper scratches especially, is to 'reduce' the look of them as much as possible, if we can get it perfect , thats a bonus !