It costs five mana and requires having multiple instants in graveyards to get value out of casting so it's a bit on the slow side and it does require setup with casting sorceries so it doesn't do everything all by itself like an overloaded Mizzix's Mastery, but despite these shortcomings it's an incredibly powerful engine helps your Spellslinger deck bury your opponents in card advantage
And since its uncounterable spot removal mode pops it into the graveyard, it also helps to fuel the deck's graveyard strategies, synergizing with mechanics like Harmonize and Collect Evidence
Unholy Heat starts as a worse Shock but quickly becomes one of the most cost-efficient removal spells in Magic
Morska, Undersea Sleuth, Raffine, Scheming Seer, and The Locust God are great commanders for draw strategies
Best to take any of these for a spin in unranked play to get used to them first
That ward ability protects him from being targeted by requiring the payment of 2 life, which will draw me a card if the player targeting Valgavoth is on their turn and hasn't triggered it yet