Anything better quickly scales from being really strong to being off-the-charts amazing
Furthermore, many payoff effects for tokens, such as power/toughness boosts and effects that trigger when creatures die, are only useful at specific points in the game, often when youre fully set up or winning
Its trivially easy to cast spells for free or buy into cost reduction mechanics like delve and emerge, and Cellarspawn just throws out damage while doing so
You can, at instant speed, do three things, but the Mana Leak won't counter anything, so what this does instead is bounce up to three things which can set back folks deeply, bounce two and replace itself, draw three cards when the bounce isn't needed, or bounce once and draw twice
Bet with your head, not over it
They're both neat ways to steal and play creatures in Rakdos, but they don't really synergize with each other as much as they provide redundancy for your game plan