The big time reward is when you come out of that risky/powerful avatar state, and transform back to Avatar Aang as four new cards, a sizable buff, and Warleader's Helix to opponent's domes is almost certainly worth it on the first upkeep possible
Royal Treatment isn't entirely a one-off effect since it grants the Royal role, with ward 1 being appreciable protection after the fact and +1/+1 being a fine boost for any trampling threat
It doesnt have to return itself, which is nice, but it forces your hand with other creatures
When you rely on very specific cards to win, the risk presented by Demonic Bargain is considerably more dangerous, as exiling a key card can take you out of the game instead of creating a significant inconvenience
There is no justice when some profit and others go without. 3/4 Illustrated by Bram Sels Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Legal Comp
You can reduce the time it takes for Wonder Stamina to recover by using Wonder Hourglasses