Mono needs a coating. It is basically mortar with dye/pigment. No surface protection.
I think most sralers are probably a combination of liquid silocone and polymer. Liquid silicone is a very cheap ingredient. The price of these sealers is ridiculous considering that the product without it will look toss after 7 years average.
Asking clients to fork out thousands on external works for it to look a bag of sh1te after 6 yrs is a bit sh1t.
Its fine applying the product, its the cost thst is shocking.
More manufacturers that release them the better. Competition for pricing begins.