As with most magician summoned items, this staff serves two purposes: it can be used as a weapon (and it's not a bad 2HB for level 16 (just a little off a runed totem staff, which is about the best dropped 2HB you would expect to see by level 16), and it gives a clickable spell effect.
In this case, the staff gives you the Gaze effect. It's the only way magicians get Gaze. It's handy for road trips so you can see that griffon or hill giant in plenty of time to take a little detour.
As far as I know, the only magician summoned weapon with an actual combat proc is the Sword of Runes, which procs an anti-summon spell, useful in Solusek's Eye or fighting shadowed men.