Many car owners and car enthusiasts have been misguided by unethical advertising into thinking that "coatings" (paint coatings) are almost a default necessity similar to doing window tinting for new cars.

The underlying causes of these misleading stories going on within the industry is mainly due to:

1. UNETHICAL BUSINESSMEN.
These "coatings" have their relevance and applications, but are not suitable and simply not practical and realistic for many types of vehicle owners and how the vehicle is used.

Would you rush out to buy the latest $1000 per pair sneakers even though you're not an exercise/fitness enthusiast? Answers will differ greatly.
If you're not a serious PC gamer, would you spend 15K to custom-build and hot rod your own PC?
If you're not even a great cook at home, will a 4K food processor + a 3K cookware set immediately make your food taste wonderful?

"Coatings" is the easiest and fastest way to make big money in the detailing + polish/wax industry.
Many proprietors immediately jump onto the coatings bandwagon wanting to make huge money asap, without telling consumers the REAL story.

2. CAR SALES PERSONNEL.
As you already know, they depend on all types of commision to survive. Sales people make $$ from vehicle tinting jobs, and from offering all kinds of extra services (polishing waxing etc). This is great as its part of customer service. BUT....there are many unethical ones who cheat by playing all sorts of tricks.
Besides getting their income from window tinting centres, sales people were also approached by coatings people to promote coatings to new car owners. What next??/ Perhaps they'll ask you to buy new rims for your new cars at 15K by giving lots of BS stories, and don't be surprised....many ignorant consumers will fall for it. These sales people have very poor understanding of what "coatings" are all about as they are not from the car care industry, and just use "direct selling" persuasion and lots of cock and bull stories to convince the poor ignorant consumer.  

I use lots of these "coating" products but STRICTLY on a case-by-case basis.

Example 1:
You have a dark/black vehicle, struggle to find time to wash car on the weekends, or the car is washed by others. As you already know, car washing, no matter careful you are, will gradually create some ultra fine scratches....especially on vehicles with soft clearcoat.  These will accumulate over time and become highly visible and irritating. The only way to remove or reduce it is to machine-compound it, and this action will REMOVE your "coating" either completely or partially.
Hence, on a daily driven dark/black vehicle, I always caution the car owner about this, and avoid using coatings.

Example 2:
You leave home before sunrise and reach home after sunset daily.
In the past, your vehicle often looks horrible from Mon-Fri.
On Sat and Sun, you struggle to find time to wash it yourself, or struggle to find a "trustworthy" place without too many people, where they can wash your baby in the same American manner that you've "learned" from mostly American websites.

Example 3:
You are not a car detailing enthusiast. You hope that this expensive "coating" will make your vehicle look "better" even if you don't have time to wash it as often as you hope to.
No layer of anything can ever replace car washing. "Coatings" are not a coat of magic armour that repels dirt, grime, and keeps your vehicle looking great.  You STILL have to wash it very frequently. There are 100% no shortcuts.

Example 4:
You want something that "lasts" on your paintwork.....to last much longer than conventional waxes and sealants.
Yes, the coating will remain on the paint surface for a much longer time. BUT...what does it do for you during that time? In the past, if you already experienced watermark problems, staining from bird shit, tree sap etc, it is all due to your style of vehicle usage and maintenance. And if your usage style and maintenance (washing etc) do not change, then the same problems will continue to happen. And even if your remove whatever you can remove from your coated paintwork, there might be residual marks that remain (common) and you'll need to machine them away.....AGAIN your "coating" will be gone or partially gone. On any coated paintwork, machine-compounding or sanding will remove it.

Summary:
Any coated vehicle must be very frequently washed to avoid the usual problems in the future.
If your "maintenance" regime doesn't change, and your vehicle usage pattern doesn't change, your vehicle will still look the same vs before doing the "coating" thingy. It's not a magical layer that can keep your car cleaner for longer. I know, I know...the advertisements told you a different thing.

But sadly, you don't find the MAJORITY of coating customers rushing home to get their other vehicles done in the same way.

Do you need a hyped-up, heavily marketed RM600 piece of screen protector for your Iphone or Samsung? Again, the choice is yours and its a great business.