So the fundamentals are strong, and more importantly they're fun
Its a big, evasive demon, it gives you a strong reason to have demons around, and it replaces itself, among other things
White shows up through efficient removal, scalable creature engines, and Angels that close games
Just as many players initially wanted to play just three Necropotence (it gets worse in multiples), players were constantly running lists with three Demonic Consultations, despite how powerfully it pulled everything together
And you can play it at instant speed - you can hold up mana and cast this just before your turn, leaving your opponents with nothing to defend themselves
Indeed, you have every required tool to dominate a late game battle, so it is key to not fall too far behind early on while still advancing your win condition