Even discounting Skullclamp ($1.99) and Sol Ring (which is in every Commander 2017 deck but, as the most played card in Commander, is still worth $3.27, even with a ton of reprintings), the Vampire deck is overflowing with artifact value, with Door of Destinies being the single most valuable colorless card in in Commander 2017 at just under $6, along with Well of Lost Dreams and Blade of the Bloodchief, both coming in between $3 and $4
Both now suck pretty hard compared to alternatives like Craterhoof Behemoth and Nissa Worldwaker and see absolutely no play
While they're certainly collector's items, the cards are not tournament-legal, making them glorified MTG proxies
As the rewards here are permanent and not time-limited, you can chip away at them at your leisure
With the engines provided by Nexus of Fate and Cryptic Command + Mystic Sanctuary, having access to at least one Jace is an additional way to end the game via his ultimate, or just find the cards that you need to piece together one of the engines
It lets you return a target nonland permanent to its owners hand for just two mana