You can understand something about your child's meatspace friends and their media diet. Chat like this may as well be 4chan discussions. It's all dynamic compared to social media that is posted and linkable, it's interactive and responsive to your communicated thinking, and it seeps in via exactly the same communication technique that you use with people (some messaging interface). So it is capable of, and will definitely be used for, way more persistent and pernicious steering of behavior OF CHILDREN by actors.

There is no barrier to the characters being 4chan-level dialogs. So long as the kid doesn't break a law, it's legal.