Most of that is simply wrong
Being able to destroy two cards for the price of one is a powerful effect and not one to be understated
This works with all permanent types, and means that if you sacrifice a treasure token, you not only get the mana from the token itself, but Korvold gets stronger - and you draw a card, too
Set in the irradiated ruins of civilization plagued by swarms of mutants, ghouls, and people with dubious motivations, these role-playing games have gained plenty of renown
Unlike the Death Deck, the DARK monsters required for release have ATK 2000 or more, so at the time it was an issue to secure the release before whether it would be an effective hit, but now even low-level monsters can be used with their original ATK or their own effects