I would love an AI therapist. But, that said, I think the majority are more comfortable with sharing emotional states with other humans. Yes, telling deep dark secrets might be easier to something you're certain won't judge you, most of the time therapy is about mundane but relatable issues people are trying to connect and process. Communicating genuine empathy or sympathy isn't likely to happen soon because it will need time for acculturation, people will have to grow up being told how to interact emotionally with an AI therapist.