Fathers are different from mothers. Babies learn that very early. Fathers have fuzzy chests, deep voices, big hands, flat shoulders. Mothers are softer and smell of the milk that soothes away hunger and fretfulness. Those are quiet, needy sounds.
Fathers are different from mothers, and no father in the history of the world has ever breastfed.
For a father to mimic female biology, either Mom has to express milk and someone has to wash the pump, store the milk, fix the bottle, wash the bottle, and put everything away, or the baby has to drink a commercial substitute that causes internal changes. And studies link the early use of bottles to early weaning. A man's shoulder is built differently from a woman's, and babies seem to appreciate the difference. After the first few weeks, most babies love getting in the bathtub with Daddy. At the end of the day, when Mama and Baby are frazzled, Daddy may be just the different smell and feel and voice and style that perks everyone up.