The price spike began just after the MTG Secret Lair EDH deck Raining Cats and Dogs was fully spoiled, and Arahbo is absent from the list
In red or black decks he is just your run of the mill one drop beater having that is comparable to Diregraf Ghoul
It doesn't matter if that artifact is still on the battlefield, still under your control, or even still an artifact
Even without Serperior Celebi can still do huge amounts of damage, and its one retreat cost means you can pull it out easily if things get hairy
Demand is a three-mana Azorius sorcery that tutors your deck for a multicolored card, reveals it, and then puts it into your hand
Yank Into Melee: In case the opponent has just swapped out a damaged Pokmon to their Bench, you can use Cyrus ( Space-Time Smackdown ) to drag them back onto the Active Zone, allowing an easy KO.