streets of new capenna card sleeves Anhelo the Deacon Commander Standard Deck Protector (100ct) for Magic: The Gathering and hidden mechanisms Streets of New Capenna: Full

One life isnt a lot individually, but if you put a ton of Extort triggers on the stack, your opponents will suddenly find themselves in a position that they cant come back from.

With the right board set up this is practically a Pot of Greed every single turn

Sure, but then you won't roll any dice as it enters and it'll be 0/0

Another concern is that the proxy cant be a marked card so that you cant tell by looking at the top card of your deck if its a proxy

"Powering Up with Chaos Impact!"

Its also just good generally in a deck with generic mana costs and/or that plays multiple spells a turn, such as an aggro deck with cards like Wheel of Fortune and Windfall or a deck with a bunch of artifacts