It principally serves to shake players out of the bad habit of evaluating cards based on how they perform in the best-case scenario by forcing them to consider what happens if their opponent has a removal spell
Equipment attached to exiled creatures will become unattached and remain on the battlefield
Then there is also a new un-Planeswalker, B.O.B
In formats where players regularly do this - like in Legacy, thanks to Brainstorm - this spell acts as a deterrent of sorts, and also balances things out by allowing you to pour as much mana as youd like into your card draw
Dont underestimate what Bubbling Muck is capable of though, as it can perform an excellent impression of High Tide in the right shell, and it can even pull off far more potent shenanigans when paired with blues ability to untap lands and recur sorceries
What I rapidly found, however, is that despite it being well-known, it's never been