They include mechanics that would be impossible to include in a standard MTG set
The eleven-mana creature has its casting cost reduced by X generic mana, with X equalling the combined toughness of all creatures you control, meaning you can drop this bad boy as early as turn three in some cases
Adding this to an Atraxa, Praetors' VoiceAtraxa, Praetors' Voice deck could give another counter to your board, as well as some additional interaction to slow down your opponents
In a vacuum, its a solid set of options for three mana, particularly as you dont have to deal damage to get those options
Bone Miser twists it even further, turning your discarded cards into a pile of resources
The aesthetic is divisive, some players find the vandalized look messy for legibility, while others, like myself, think it perfectly captures Deadpools habit of breaking the fourth wall