Having effects tied to creatures is good because creatures affect the board
In Rush Duel , Zombies went though a period of extreme under-representation at first: while the earliest Zombie Deck, Toombs' Ghost Story, was featured in the very first SEVENS arc, it would take until mid-2022's Megaroad Pack (after the end of the series) for it to be printed, with only 6 other Zombie monsters released in the intervening 2 years.
Why it makes the blood token is probably the discard it can provide, but Im sure it will be a fine addition to Strefan, Maurer Progenitor and Anje, Maid of Dishonor decks everywhere as well
Lastly, that Charizard included in the set could actually collect some value
Others, like Silence, are one-time effects that last until the end of the turn but completely lock them out of any spellcasting
Epic cards replace the foil slot in booster packs, similar to Enchanted cards