I made it easier for you to understand.
Using a car polish is like buffing a fingernail. The abrasives in a nail buffing cream remove dead cells and ridges from your nail and leave it clean, smooth, and …yes…shiny. A true car polish works the same way, by abrasion. Because of its abrasive properties, a polish is very good at removing scratches and swirl marks. It also conditions the paint, eliminates light oxidation, and creates a high gloss not possible with car wax alone. It’s also important to note that a true, pure polish leaves nothing behind on the surface.
Also keep in mind that since polish is an abrasive, it’s important not to overuse it. I know a few car enthusiasts who only use polish on their vehicles. I wouldn’t recommend this. An occasional once-over, plus some spot treatments for minor scratches or swirl marks may be all you really need.
A car wax is completely different. Back to our fingernail analogy, a nail polish, though it’s called a polish, in reality works more like a wax. It imparts its properties onto your nail, thus enhancing the shine, and protecting it. In the same way, a car wax leaves behind a layer of material which then brings out the depth of shine in your paint as it protects your paint’s finish from oxidation and harmful road debris.
Therefore, a good polish needs to be followed by a good coat of wax for added shine and protection.