The wax or sealant seals in the solvents that need to evaporate from the paint.
Would someone please explain to me how this stuff is supposed to magically penetrate through the clearcote to evaporate, which is essentially hardened plastic. I just doesn't make any sense to me. I keep hearing this stuff come up with out any really good supportive chemical theory. Solvents in paint would evaporate very quickly. Try pouring some solvent cleaner etc. on anything and watch how quickly that stuff evaporates, this stuff would evaporate before you could even spray the car with any clearcote. Yet they wait before even spraying the clearcote on the car, so if there were any solvents evaporating etc. they should be long gone into the exhaust fans or some poor saps lungs.