Prior to the Evolution of Combat, all of the croziers were equal to battlestaves in both attack and defensive stats. After the Evolution of Combat, croziers have a magical accuracy higher than even the Mystic staves in addition to the +6 bonus to prayer. Battlestaves and Mystic staves however can be enchanted to allow for infinite casting of certain elemental runes and croziers cannot.
On the update of 24 March2014 Croziers were changed dramatically. The Ancient, Bandos and Armadyl croziers were made 2-handed and had their prayer bonus changed to +6 instead of their old +3. Besides that they were made a typeless weapon which can not be used for combat.
Even though croziers cannot be used to engage in combat with, they can be keepsaked to override all staves.