I bf. At first because it seemed easier than boiling kettles. Then because I realised how important it was.
Most know the basics, fewer infections, less obesity, lowers risks of certain cancers for mum etc.
But where formula contains fats, carbs, proteins, vitamins. That's it. Literally it. And the fats especially vary in provenance according to price so you don't actually know what you are feeding your baby. Yes companies put stuff on that sounds good but it doesn't have the effect the human version does because it doesn't come from humans.
Breast milk has the right balance of nutrients. It has viral fragments to help kick start the immune system. It has hormones, not just oxytocin for brain development and bonding but your thyroid hormones, insulin etc to help baby transition to life until their own system does it themselves. Transfer factors to absorb nutrients, special factors to absorb iron so it isn't around in the gut for bacteria to use to grow and spread, it lines the gut so bacteria and viruses can't escape and infect the body. It has so much more than nutrition.
Of course formula is nutritionally adequate and I think it is awesome that we have something that can grow a baby in the absence of breast milk and sometimes it is absolutely necessary but nothing can ever replicate the protective factors in breast milk.