Pair it with something that untaps creatures when it enters the battlefield, and the loop creates infinite hasty tokens, which usually ends the game on the spot
This isnt the case for other types of cards, or abilities that are passive
Your opponents wont be able to fetch their lands or tutor for their combo while the Arbiter is there unless they pay 2 mana more
It also synergizes particularly well with Fetch Lands, since you dont end up losing a land by the end of it
They make for awful late game topdecks, but they can fix your colors and accelerate out a 4-drop on turn 3, which is something nearly every green deck is interested in doing
With this mono-blue Human Wizard in play, all your creatures not on the battlefield gain flash, letting you cast them at instant speed no matter where they are