The study coauthor actually seems positive on their potential:
'LLMs potentially have a really powerful future in therapy, but we need to think critically about precisely what this role should be.'
And they also mention a previous paper that found high levels of engagement from patients.
So, they have potential but currently are giving dangerous advice. It sounds like they are saying a fine tuned therapist model is needed because 'you are a great therapist' prompt, just gives you something that vaguely sounds like a therapist to an outsider.
Sounds like an opportunity honestly.
Would people value a properly trained therapist enough to pay for it over an existing chatgpt subscription?