Amethyst/Ruby can be useful for control decks focused on maintaining sway over the board, while a good Emerald/Steel build tends to angle for weakening an opponent by depleting their resources through discard abilities
This basically allows you to be really aggressive, lean into a lesser-known tribe, and also play with the discard theme all at once
(They cost less to cast for each Aura you control.) Whenever you cast an Aura spell that targets a modified permanent you control, draw a card
Either way, the ability represents big-time card advantage if it lasts a couple of turns
Dina's an engine in and of herself, with an ability that allows you to draw a card once per turn when you sacrifice a creature, and another where you tap her and pay two mana to sacrifice a creature
What do you think of the creatures in blues arsenal