[Taqwus]

The trident gives quickness, which can be useful for a mage whom you would not give other hand gear to -- e.g. will not be giving a Staff of Elemental Mastery etc.
Early on, the XP bonus is also likely to land the winner a spot in the Hall of Fame and thus a heroic ability.
Even in SP, I sometimes sit out the first match and see what the AIs send; if a pretender wins, I'll prepare a few "gifts" for the next contest.