Are ceramic coatings just snake oil?

No, they aren't, but some of the claims made about them most certainly are.

There are a few brands that everyone wants to sell, mainly because they are well known. They are established and have a good reputation. They do what they promise to do, and so for competitors, it is going to be hard to catch up, let alone knock them off the top spot.

When you are selling a layer of microscopic ceramic which is invisible to the naked eye, it's pretty difficult to differentiate yourself from the competition. Some will try and bundle up their coating with some other service, like key finding, air miles, or something else you can easily live without. Other's will make outlandish claims or resort to parlour tricks.

For the record, before ceramic coatings ever existed (and possibly before many of us were born), there were salesmen setting fire to lighter fluid on the bonnets of cars, claiming it was completely scratch proof, or you will never have to wash your car again. It was all nonsense then, and it's nonsense now.