What's the difference between a bath bomb and an Epsom salt soak?

Bath bombs are primarily a sensory experience: fizz, color, scent, and skin-conditioning oils. Epsom-salt soaks like Dr. Teal's are pitched more therapeutically, with users in fibromyalgia and skincare subreddits reporting relief from muscle soreness. Many soakers combine both, dropping a bomb into a tub already mixed with Epsom salt.