I have very little experience using magic staffs as proper weapons. But, from what I know, they are pretty terrible as pure weapons if you lack the appropriate casting skill.
Magical staffs have up to three effects: A) They act as an enhancer for the appropriate magical skill (fire, ice, poison), or have some other more specific effect (reduce spell hunger, reduce spell failure). B) They give you one point in resistance for the appropriate resistance assuming they are a elemental staff. C) If it is a elemental staff, then they give you a chance of extra damage dependent upon your skill level in the appropriate magic school.
This means a few things A) they are far more useful for casters (who can use their enhancing ability properly), B) Elemental staffs have almost no bonus damage at all if you lack skill in the appropriate school of magic (and its not worth it to train it just for the staff), C) *I think* they are pretty crummy as weapons even with the appropriate school (although I am not really sure), but if you are a caster you will be using magic all the time anyways (and a enhancer is worth using a weapon slot), not trying to bash stuff in with it.
They also lack the ability to be enchanted, so even if it starts out as a decent weapon, they become crappier the further in you go.
EDIT: tl;dr: If you aren't a caster, and don't need the specific resistance (poison/electricity) don't use it.