Still great in artifact/enchantment, enchantress decks, but those are narrower than decks that play instants and sorceries. #6
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
I am the Arch-fiend, the Despoiler of Worlds, and by my hands shall the false Emperor fall. Abaddon the Despoiler Illustrated by Games Workshop Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Legal Comp
With only one of each basic land, I'm looking at that rare "true" singleton EDH deck
The most common use is to put an infinite number of counters on Animar, Soul of Elements