Amber brings healing and supportive characters that allow you to recover from early aggression, while Amethyst adds tricky control tools that can block, bounce, or stall your opponents biggest threats
Also, and this is the main bit, you can exile it and the parts of Vecna to create an 8/8 Legendary Black Zombie God token with indestructible
For just three mana you can tap Brash Taunter to force it to fight another creature, except when Brash Taunter is dealt damage, you also deal that much damage to an opponent
Just a few more additions
The only miracle here is that this card didn't end up higher on the list, which is a product of the cards around it
Once you start building with three or more colors, your removal options improve, but this is still solid