Why do people use Astringent or Toner?

Toner is good after you wash your face because when you wash your face, the soap does leave a film on your face and also toner gets some of the oils/grease that clogs your pores.Why do people use Astringent or Toner?
Toner is very important for your skin. if you wash your face, tone, then moisturize, your skin will look 20 years younger. I know when im 50 i dont want wrinkly skin!Why do people use Astringent or Toner?
to tone...it eliminates ';jiggling'; of ';fat';