No one wants to pay the ward cost to get rid of him, and every time anyone casts a spell, you get another Amass trigger
You can keep your commander as the last creature standing after the climatic Saga resolves with a little proliferation to force the second chapter in the same turn
Until it does, its a good mana rock that lets you cast the things in your hand so that its (close to) empty at midnight
A slam dunk in mono red, and playable outside of it still too
Since Arwen is the lowest-mana-value way to create indestructible counters in that decks colors, it has become one of the first recommendations experts make for upgrading that preconstructed deck
Falls er dies tut, ziehst du entsprechend viele Karten, erzeugst entsprechend viele getappte Schatz-Spielsteine und verlierst dann entsprechend viele Lebenspunkte