Its also graveyard hate that also stabilizes you with life gain or pushes the last points of damage on your opponents, and one of the best shamans in the game in case its creature type is relevant in your deck
I would compare it to how adventures allow you to potentially use both halves of the same card, except Rooms allow you to play their halves in either order
Massacre Wurm has a nice -2/-2 enter the battlefield effect but, more importantly, deals two damage to each opponent whenever a creature dies
Spit Flame is a target removal instant that is recurred on Dragon ETB, something that works well with our Dragon Tokens produced by Vrondiss, Rage of Ancients, making it a repeatable removal
Now its your turn, who do you think is in the mystery Amethyst card and do you think well see another Flynn rider card?
This deck can very quickly generate an absolutely enormous army and completely overwhelm your opponents