A robot has infinite patience and will never get mad or bully a child for fun. Ideally, this should also be true of a parent, but it’s not. From a less grim angle, a robot doesn’t have other responsibilities like work.
For a kid who feels too shy to talk to people, a robot can be good for practice. But it requires a lot of attentiveness from parents to make sure the child doesn’t become dependent and moves on to taking to people once they get their confidence.
Back when drag was a kid, we used imaginary friends instead of robots. But a lot of parents and children don’t believe in imaginary friends, which is a shame, because robots are a lot more expensive.
You should go watch Big Hero 6, then. You’ll get a very good idea of how a robot can be supportive.