As I've already explained, discard spells by their very nature are unfun as they prevent things from happening
1 Mana Crypt Well, It Does In Fact Flip A Coin Calling Mana Crypt a "coin-flip card" is cheating to some extent
For example, if your graveyard contains only Tree of Tales and Nameless Inversion, delirium abilities will be active
In sum, it's evoke and plot's secret child
It's strong in most mono-Black decks, blink decks looking for lands, ramp decks looking for more ways to ramp out lands in the creature base and midrange decks that have loads of card advantage ETB dorks like this to use and abuse
For example, Karador, Ghost Chieftain wants to tap out on your turn, and the two cards are simply antithetical