I would definitely do it for both in the case of harm, but not always for healing. AW is a dangerous place, so there's plenty of opportunities to take Harm from external forces (threats), which means a Hardholder lucky enough to have an Angel could potentially gain a lot of Hx just in the normal course of play. A PC causing direct harm to another, even using a third PC as a weapon, is a more momentous (and memorable) occasion. Hell, I might be inclined to offer Hx if a Harholder refused healing, if doing so would cause Harm (if the PC was after 9 o'clock, for instance).