Cura Top Surface Skin Layers. How do they work? Should you use them?

Still working on getting the best top surfaces possible!

Ender 3 Pro at Amazon - https://amzn.to/37iVaYv
Ender 3 V2 at Amazon - https://amzn.to/2Wf3SAP
Geeetech A10M $279 at Amazon - https://amzn.to/2HYXeLz
Qidi Tech Shadow 5.5s resin printer at Amazon $149 - https://amzn.to/3f4Rfkn