It's best for baby. Breastmilk has antibodies in it from the mother that pass to the baby and help protect him against illness and allergies. Breastmilk is easily digested. Mothers don't have to worry about their babies being constipated or thirsty, because babies get an adequate amount of water from breastmilk. Sucking at the breast helps with good oral development.
Breastfed babies have fewer speech impediments.
Breastfed babies have good cheekbone development and jaw alignment. Consequently, there is less chance of needing braces and other orthodontial work. Breastfeeding also is good for the mother. The baby's sucking at the breast causes uterine contractions right after birth. The contractions lead to less bleeding for the mother, and return the uterus to its pre-pregnancy shape much faster.