In addition to your main decklist, these formats allow a secondary list (almost always 15 cards maximum) that act sort of like substitute players in traditional team sports
C Common Hysteric Party X TRAP Continuous Activate this card by discarding 1 card
For X and two Black mana, you get a sorcery that makes each opponent lose X life, and you then gain life equal to the amount lost because of the card
By adding Black, Wort brings some Sacrifice and graveyard strategies into the standard Goblin game plan
Both two-cost cards satisfy Moana, Self-Taught Sailor requirement, allowing you to control the board early if necessary and set up for big lore-gaining turns soon after
Also, since the most expensive Enchanting Tales are reprints of popular, tried-and-true cards, Id guess that their prices will be more stable than brand-new main-set cards (which include a much bigger shiny-new-toy hype factor in their prices)