In Diablo 2, giving your mercenary a weapon will vastly increase their effectiveness. Giving my Act II mercenary a 3x socketed pole with Rubies or Topaz for example basically lets them 1-hit everything right up to Duriel.
I've replaced said Pole-wielding mercenary with an Ice Act III mercenary. Reason being that Glacial Spike freezing 3+ enemies is obviously really effective.
This mercenary seems to already do pretty nice damage, but they can still accept a weapon (I think a sword-type weapon and a shield).
I've never seen this particular mercenary ever use a melee attack before (then again, I don't pay much attention).
So, other than having properties that would affect magic damage, resistances or similar obvious benefits; does the weapon help the damage of my mercenary? Maybe it impacts the magic damage even though it would seem odd to do so?