MTG's Intangible Effects Are Better as Neutral Cards, Like Planechase One-sided, intangible effects like The One Ring's temptation emblem feel like cheating, giving one player a weapon that the other player can never counteract
The ability even encompasses your own life
Slowly filling with oil as you tap it turn after turn, the Sylex gives you the option of sacrificing it to sweep away everything of a specific mana cost, like a worse Engineered Explosives
Overall, one of the best stax cards (that's to say, effects that slow down your opponents and basically prevent them from doing anything) you can play
Or rather, they can do so, but it's counterintuitive and is likely to turn your commander from a decent threat that's hard to deal with to a game-ending wrecking ball that can dish out 21 commander damage in a single turn