Clients often come to therapy with significant difficulties that take significant dedication and effort to overcome. Yet they are often accustomed to standard medical care, in which the clinician does almost all the work and produces remarkable results with a minimal patient role (e.g., splinting an agonizing broken wrist; or prescribing antibiotics for a raging case of strep throat).
Mindfulness in the context of psychotherapy is more than just a technique or a theoretical perspective; it is a way of being with and relating to experience. Regardless of whether or not you choose to incorporate formal mindfulness practices in your sessions with clients, having your own mindfulness practice will positively inform your work.
While it’s certainly not a requirement, many who are drawn to become mindfulness facilitators are trained psychotherapists. And many of the skills of psychotherapy, such as managing the group dynamic and building rapport, are assuredly useful in facilitating a mindfulness group.