A planeswalker's health is represented by its loyalty, but just like your own life total, a planeswalker's loyalty is a resource
[1] If your "Nekroz" card is banished, face-up: You can target 1 Spell/Trap on the field
Leovold, Emissary of Trest Leovold, Emissary of Trest sees play in formats like Legacy and Vintage, and it was so powerful that it was banned in Commander
The grading scale will usually look like this: Near Mint (NM) Almost perfect condition with minimal wear
So, WotC did do a solid job of crafting these decks to keep the action moving, preventing too much turtling and one player from just crushing everyone else
One way to use your opponents' decks against them is to outright take what they already have