For me hard coatings means even watermarks shouldn't form, if it's hard to remove it means the water mark has done deep into the coating, and to remove it you have to remove even more coating which defeats its purpose.

Without coat: you worry about paint.
With coat: you worry about coat, no more worry about paint. It is easier to re-coat than re-paint.

Let's see .....

A buyer pays RM750 for a Sierraglow coating.
He must maintain the coating by washing, claying and drying the car.
I estimate this maintenance will easily take 2-3 hours to do.
And he can't send it roadside RM10 car wash coz they don't exactly do claying right?

Every week need to spend 2-3 hours to wash, clay and dry the car 

or else pay more $$$$ to send back to Sierraglow