Virtually all therapists recommend some form of drug to clients. Every therapist I've ever seen has insisted I see a psychiatrist for meds, despite my problems not being all that severe. I'd rather my therapist insist I smoke weed then continually tell me I need to be on Xanax. And this therapist didn't tell OP to smoke weed. OP told therapist that OP already smokes weed, and therapist said okay, if that's what works for you.

Would it be ethical for a therapist to insist a client not smoke weed, if the client felt weed benefited them? I think it would be highly unethical for a therapist to convince a depressed person to quit using antidepressants, if the depressed person benefited from the meds and didn't want to quit. Why is this different? If the OP develops a dependency, then they can talk to the therapist as that arises.

If the OP sees their usage as a problem, then they should talk to the therapist about that. But weed is widely considered medicine, and where I live, legally prescribed for a variety of mental illnesses. All the therapist knows is that OP smokes weed because weed makes OP feel better. As far as therapist knows, the weed usage is medicinal, and it isn't really their place to intervene, unless OP expresses the usage is becoming a problem.