With other complementary artifact mana sources like Thran Dynamo and Grim Monolith, decks could count on being able to get the kind of mana you'd need to justify packing the cards that would let you use the mana from Metalworker to deliver the knockout blow, and their presence lets you turn that Metalworker mana into permanent giant amounts of mana rather than just a one shot deal
Rather than trying to painstakingly copy out mana symbols or using the names of the MTG colors, Jeff's makeshift cards use the initials of the five MTG lands, (PISMF instead of WUBRG) to make it easier for others to learn
I love this with a sort of Voltron build too
Repeat his performance and earn his second Pro Tour Top 8 in as many events
Sacrifice after III.) I Crescent Fang Search your library for a basic land card, put it onto the battlefield tapped, then shuffle
Even though your opponent might remove some of your creatures, they still need to deal damage to win