Distrust? It helps to know if they napped or not, because that changes plans. Doctors ask about diaper change schedules. Bumps or scrapes are good to know about because not all effects are immediate.

It's not about trust. People forget shit, and comm lines get crossed when you're working with 4 other staff and 30 kids. Why rely on someone's memory when the alternative is faster, more consistent, and more informative?

People in general are faulty machines with shitty brains and worse memories. Add on that they're working in an extremely chaotic environment, usually overworked and understaffed. It would be literally fucking insane to expect them to remember everything that happened to every kid, and that's not even factoring in that each of the staff has completely different touchpoints throughout the day.

Are you this unaware of how people actually function?
I wouldn't go so far as to call it braindead, because that just needlessly antagonistic, but we have a lot of evidence that people forget truly important things all the time, particularly in a setting where a group of people are working together to care for others.
Nurses and doctors will forget they administered medication and give double doses. People will forget that they needed to toss the spinach from the line because it's coming up to its safe lifetime and get people sick.
It's why we have checklists and logs where we write stuff down.
If my local coffeeshop has a checklist and log where they document cleaning the bathroom and doing a deep clean on the espresso maker, why on earth would it be unreasonable for the significantly more important job of "caring for babies" to also do so?