In DnD some people talk about "spear bows". To exaggerate this I came up with a Broom of Flying, which can be used as a quaterstaff and a longbow—both dealing magical damage as weapons made of a magic item.
Please help to find counter arguments, even to ban spear bows from game. There must be a reason, why medieval people aquired longbows only in a case of emergency as melee weapons (esp. when carried with the string relaxed), and never put a metal sting on its ends.