Why does Gluma Desensitiser /Gluma Desensitiser PowerGel need to be air-dried prior to rinsing off?

Air-drying increases the desensitising effect

After application on the hypersensitive tooth area, GLUMA Desensitizer/GLUMA Desensitizer PowerGel needs to be airdried. This step increases the desensitizing effect. Afterwards, the desensitizer needs to be rinsed off using plenty of water by the dentist/ dental assistant.