You don't have to choose a target artifact or enchantment for the last ability
Instant-speed removal for just one blue mana is clutch, and often well worth the price of leaving behind a vanilla 3/3 creature
Once you have one or two of these token-doublers out, you can swarm the board with cards like Secure the Wastes and Martial Coup
Not everyone was in love with the upkeep cost of Lord of the Pit, even though Fallen Empires Breeding Pit made the cost seem easier to maintain, Sengir Vampire was a simple power flyer and if you played your cards right, easily pumpable
Boxing Ring: Green has never been great at removing creatures, but a two-drop artifact that allows your creatures to fight enemy creatures and then create a treasure if they fought this turn is a decent way to help clear the way for your big stompy bodies to get through for combat damage
If youd like to see a more visual guide, check out the MTG Fetch Lands visual guide