The answer is: YES.
Doing better than nothing is a really low hanging fruit. As long as you don't do damage - you do good. If the LLM just listens and creates a space and a sounding board for reflection is already an upside.
> Until we answer the question "Why can't people get good mental health support?" Anyway.
The answer is: Pricing.
Qualified Experts are EXPENSIVE. Look at the market pricies for good Coaching.
Everyone benefits from having a coach/counseler/therapist. Very few people can afford them privately. The health care system can't afford them either, so they are reserved for the "worst cases" and managed as a parse resource.