Enhancement VS Correction

Paint has a clear layer of paint over the colored paint. When you get minor scratches in your PAINT they are actually in the clear coat and not the actual paint.

Polishing is basically a very fine buffing compound that is like fine sandpaper. Buffing out the minor scratches is removing tiny amounts of the clear coating which can remove most MINOR scratches. If those scratches are deep enough, they can damage the paint that is underneath the clear coat. This means the PAINT may be damaged. Polishing will not repair this. It will only enhance it. 

There are many examples of paint enhancement.

Paint enhancement means... improve or make it look nicer. This in turn means that some imperfections will remain. 

Paint correction means to repair damaged paint. Damaged paint cannot be corrected with a polisher/buffer.