Also they're the same color. If you're so deep into black that you're casting a BBBB spell, presumably others at the table will have less equity in black.
What about a red creature that enters with a +1/+1, but you can remove a +1/+1 counter from it to exile the top card of your library and play it til end of turn.
I will say, as much as I'm not super a fan of Upheaval / Armageddon, these cards have led to some super interesting games over the years. When you cast one of these big spells and the game doesn't end immediately, things can get juicy.
I was cleaning out my Google Drive and found something from 2015 that I called 'Chess Drafting'. I have no recollection of ever doing this, but it looks pretty dope.