Maybe m late to answer, but here is what i know. Ceramic coating is liquid silica. Its glass in liquid form. Made in china, comes in drums, and then packaged in small bottles, and sold for 1000% times its cost price. Its kinda permanent thing but if need be to remove it, u need to grind it out, or cut it out via hard compound process.
It does only work with paint. Only bond with paint. Interior coating, plastics coating, anything else is false and fake. It only bonds to painted surfaces. The main benefit is you can wash your car with sandy cloth and it wont make swirls marks. If a stone hit your front at highway speed, it will cause damage.
Paint correction is simply if you have scratches, even on the new vehicle, that part have to be buffed out, idea behind is same, you are going to apply somewhat a permanent layer on top, so better start with a scratch and swirl free clean paint. If the dealer washed your new vehicle before delivery with a dirty cloth, then it will result in swirl marks, may be microscopic, but a dirty cloth will always introduce micro scratches, that you can only see with a light. So mostly new vehicles need none or very little paint correction, but you will be charged for a full service.
Now imho, clear bra is better option, though it changes colour after a while, like may be 2 to 4 years later, but protection is there. The self healing ones are good products, just go to amazon and buy a roll and watch a youtube tutorial on how to apply it. If some one quoted you 10,000$ for a full car, you can buy the material in less than 1000$, rest is all application fees. which anyone can do.
And one more thing, all this is excessive not must do'sss.. unless you are going to keep the vehicle for 20 years, and after 20 years you wana say to your peers, hey look at my paint, its still like factory. Besides, there are other factors, like if there is a little dent on a door, then you have to redo the full door.
The only thing.... thats important now......pay attention.... the only reason i do ppf on all my cars, is keying, people deliberately keying to scratch your car. This is the only main benefit i can see. If you live in an area full of jealous ****** bags. Then ppf is well worthy investment. Natural dings and dents are natural. Its part of the game. and i wont notice them either, but when people make a full scratch line from front fender, thru the doors, to the rear with a key or even screw driver, i want to burn them alive, kill them, make em alive again and burn them again and repeat till eternity.........say "hell ya" . if u agree