Transitioning to cow’s milk really necessary? Please explain

Maybe I’m stupid but I don’t understand the “need” to transition a baby from breast to cows milk. My baby is ten months so I’ve seen this topic come up quite a lot lately. I don’t understand the need to make a baby drink the breast milk from another species? I’m not saying that as a vegan or anything! (I’m actually vegetarian) - I just don’t understand it.

Am I right in thinking that there ISN’T an actual “need” to transition to cows milk? That I could just keep breastfeeding and offering her water and a range of healthy solids until she’s ready? I’m sorry... am I missing something? Isn’t goat’s milk healthier, anyway?

In other words... What is the benefit in transitioning a baby off their mother’s breast milk to the breast milk of another species? I always expected my baby to simply let me know when she’s ready for a normal diet, without the need for a “transitional” milk in-between.

This post isn’t meant to sound accusatory or confrontational in anyway - I just genuinely don’t understand it. I haven’t heard of any actual benefit to the child. Maybe just that the mother wants to wean sooner? But I could be completely wrong about it, so I’m asking you lovely women, if you wouldn’t mind explaining? X