Therapist is a bit of a misnomer. Therapy or treatment is when something is applied to a person to help remedy or alleviate their ills. Therefore a psychotherapist is applying psychology to a client to remedy or alleviate their mental health symptoms. But you can't apply psychology to a person. A person has to learn to apply psychology to themselves. Therefore what they need is someone to help them learn and practice applying psychology, which is precisely what either a coach or a counselor does. Ergo coaching and counseling are basically the same thing. The difference is counselors and social workers have worked hard for yours to have their services recognized as a necessary component of health care, which brings it under insurance reimbursement. State's license health care providers of all kinds because they have an obligation to ensure they are channeling Medicaid recipients to competent care. Most insurance company's follow these same guidelines for reimbursement. The guidelines of severity of problems or dysfunction to constitute a mental illness are a bit of a grey area. Coaches serve the population on the ample fringes that don't meet the severity requirements for mentally ill. But they are teaching their clients to utilize the same psychology a mental health counselor will teach.
If there is a difference between coaching and your standard CBT counseling, it is that counselors are expected to do gradual exposure and assess for suicidality. Those would be the 2 hallmarks of mental health treatment that coaches would probably not anticipate and know to deal with. Now, the importance of those two hallmarks can not be emphasized enough. They are crucial to treating mental illness. They are literally life and death. But it bothers me that the distinction between counseling and coaching is that counseling is life and death while the stakes of coaching are nearly level of happiness, because it overshadows and denigrates all the "coaching like" work counselors do much of the time.