Yugitards lament and cry about the fact that one of the most powerful cards ever printed, is useless and too slow in modern Yugioh, where turbo autists summon half their deck in one turn

Card advantage is EVERYTHING in yugioh. The modern games however has many cards belonging to Archtypes or specific themes. These archtype cards often have BROKEN effects and card draw ability but ONLY for other cards of their archtypes. Pot Of Greed has simply been rendered obsolete with dozens of other spells and monsters have much more specific card draw and range. Plus with modern spells and monster effects now being able to activated in an opponent's turn from the hand, known as "hand traps", Pot Of Greed as a normal spell card with no quick effect modifier is also way too easy to shut down.

It's great in floodgate.dek since you want to drag games out but not much else, the issue is you're sacrificing handtraps and a pretty large number of monsters that summon themselves by activating in-hand, not seeing any immediate benefit, you aren't going +1 in card advantage until the turn after next, and on top of all that if you ever get into a situation where you're reliant on your draw topdecking Morganite when you haven't already used it is an instant loss.

The card in the reddit post is busted though, I'd play it.

It's the turn delay. It's not going to be relevant for a lot of decks since it's a contingency card if you don't get the right start, and your opponent doesn't either.

It's why Shard of Greed (draw two cards in two turns) isn't limited but Pot of Greed (draw 2 now) has been banned forever and would slot 3 into every deck if it wasn't.