Personally, I don’t want to share photos of my daughter because I don’t think it’s fair to share her photos when she’s not old enough to give consent.
There’s also the issue of privacy and not knowing who is looking at your child’s photos and what they’re doing with them. There are some cases where men are creeping on three-year-olds whose parents post their photos online and saving those photos (or even photoshopping ones where kids are doing something innocent like eating a hotdog…). It’s awful what some sick-minded people do.
I don’t mean to fearmonger, of course, but these are key reasons why I will never share my daughter’s face online publically unless she allows me to. (Even then I don’t know if I will…)