Why wouldn't someone just use Instagram and take pictures of their babies?

I agree. But it seems like it would be a great niche. kinda like a virtual timeline of your child's life. I could see baby/kid brands signing up on the service.

Hmm.. I guess you are right. I suppose there will always be a market for "X for Y". Take successful "general" product and specialize it.

Yep. Could be interesting.