Actually, there is! Attune Farron Flashsword, walk right up against someone or something you want dead, and smack it. The magic blade will hit it, and so will your staff, dealing an extra whole 1 or 2 physical damage, as a separate hit. So, technically there is a spell that let's you deal physical damage. This is actually somewhat useful, despite the ridiculously low damage of the staff, since you can potentially trigger someone's Tears of Denial and kill them, in the same attack, due to the fact that the damage seems to be applied separately.