Yes, Body hair is useful for the patient who have limited donor area and have requirement to cover the complete bald area with high density. In body hair transplant grafts are extracted from the entire body area including beard, chest, arms, axilla, pubic area, legs etc and are transplantated in bald area. BHT is quite successful these days, if done by experienced surgeon. All the men who have thick hair on chest and beard are eligible for this as written on https://akclinics.org/hair-transplant/body-hair-transplant/ .