The vast majority of babies I see as patients in the out of hours setting are formula fed. They get unwell more frequently, have higher risks of allergies, viral wheezing, colic, reflux and are generally less settled.
Human breast milk is perfectly designed for humans. It contains the lowest amount of protein of any mammalian milk, and the highest amount and variety of pre-biotics to feed the developing microbiome. Live probiotic bacteria are also present in breast milk. The exact make-up of the milk changes all the time to suit the baby.
Formula milk is ultra processed food for babies, and contains natural bovine growth hormones which negatively affect our babies. As
@mrln said, it is also expensive to formula feed.
Sadly a lot of the patients I see say their midwife encouraged bottle feeding! Breast is definitely best, but for those mothers that physically can’t breast feed, they need advice about helping their baby develop a healthy microbiome (eg using baby probiotics).