A seven-mana Equipment that only provides an equipped creature with +1/+0, Elbrus's power lies in its ability to transform into Withengar Unbound if the equipped creature deals combat damage to a player
The deck starts by casting 2 strong 2-drop creatures in Youthful Valkyrie, which is an effective early-game blocker and grows with your angel army, as well as Giada, who is devastatingly strong
You can use it to save stuff from mass removal or targeted, protect something post-bounce, and a lot more
The structure of the packs means that they are more likely to include rarer cards, and some variants only appear in Collector Booster packs, but there are no guarantees that you'll pack a certain number of valuable cards per pack or box
But the big difference is in the first ability: For decks that play cheap creatures, a 1-mana discount is huge
You have to do this for each individual card