Toners are design to hydrate your skin an prepare it to absorb the rest of your skin care products.
Think of a grape and a raisin, the main difference between the two is the water content! A grape looks plump and smooth while a raising is wrinkly and dry. The more hydration you add to your face the healthier it will look and feel!
Skin that is healthy and hydrated will absorb skin care products better, so think of your toner as a primer for the rest of your skin care routine.