They get uncastable giant creatures out of our hand and into the graveyard, they refill our hand with fresh gas to play, and of course, they trigger Sefris (so long as we discard at least one creature)
One of those cards is Werewolf Pack Leader, an aggressively costed Werewolf that offers card draw
It has a resilient, straightforward game plan and is packed with valuable cards
It wont spark any new decks, but Dread Fugue is a good tool to have in the Rakdos Arcanist (Lurrus) toolbox
You can take a creature with just two counters on it to four, putting it above what your opponent would consider to be fair trade when you move to combat, leaving them with not many choices on what to do
On the one hand its clearly a bad card