The upside of a heavily discounted extra turn doesnt quite make up for the potentially wasted card, but this does good work in decks that manipulate coin flips or can copy it several times over to increase the odds of getting at least one turn out of it
You will often catch people out with it as well as they do not expect you to disrupt them with a Stifle effect even if they are expecting countermagic
I don't think any other sliver creatures are worth it for this combat-focused version of Slivers
Life Insurance Even more niche, even more crackable, Life Insurance gives you Treasures instead, which is nice in a fair deck, better in aristocrats, and it goes infinite with a variety of combos, like say, Ashnod's Altar with something like Reassembling Skeleton and Falkenrath Noble
And accept that sometimes the best decision is to passbecause in a brand with this much output, another attractive window is never far behind
By the fourth turn, she was challenging my characters to stop them earning lore