I'm not as concerned about the leak or children's privacy here as I am about the actual recording of conversations. Think: child playing with creepy AI toy near parents having a political discussion.
Internet connected and corporate controlled microphones are a bad idea in a world where (yes, first world) governments are eager to squash dissent.
Chat bot for kids toys sounds like a great idea; i'm sure they have the mental capacity and context to comprehend that they're interacting with a stochastic predictor machine.