well, hell swords are cheaper, and, it is true, the blood thorn is pretty sucky as a weapon - good enough against chaff, but not what you want if you end up in a duel w/ another SC.
but blood thorns are ideal for Magoth and Bifrons who both need time to cast a full complement of buffs and who can include astral weapon amongst them; making the blood thorn a rather frightening drain weapon
