Nope, the moxa is the fluff from the leaves of mugwort. Mugwort (yomogi) is also used as an herb (yomogi sweets, yomogi udon) so the smoke is fragrant. It’s kind of minty? Or like the scent of tomato leaves, a little?
It’s often used in combo with acupuncture. So. Probably not supported by research, but been around for a thousand years