MK18Pilot is correct. Anodizing is already rough.
Cerakote and most all other spray on finishes are glorified paint.
Printable View
My ak is coated black in Cerakote. The first time I adjusted the front sight the coating flaked off just from using the sight adjustment tool. It's parkerized underneath so its not a biggie but I dont think any if the spray on coatings are as durable as good old phosphate or anodized on something that is gonna get used a lot.
Colt coming out with anodized receivers other than black is one of the most significant developments in the AR-15 world over the past 10 years.