kiryu yugioh card price - Kairyu-Shin Yu-Gi-Oh - Kiryu - MFC-009

The reason for this is the flexibility that Devotions payoff cards have

The Speed Demon The Speed Demon will draw you some cards on top of an already good body

Partner Legendary Creature - Angel Inniaz, the Gale Force Flying : Attacking creatures with flying get +1/+1 until end of turn

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