These all stack up to a Radiation trigger that occurs on each players main phase
Although its high mana cost makes it more useful for Commander or Selesnya decks, it is a late-game win condition if it can reach the battlefield
So, if you move or remove the last counter, the planeswalker is effectively destroyed, even though its not technically destroyed by a spellit just dies because it has no loyalty left
Metamorphosis Fanatic Metamorphosis Fanatic is 6 mana (or sometimes even 2?) for a good body, plus a reanimated creature that gains lifelink
Finally, Red + Green Burn tends to punish what Green hates, namely all-things winged or artificial (Clan Defiance, Cindervines, Ruric Thar, the Unbowed, etc.), or staples Burn onto already-useful effects (Vengeful Rebirth, Exploding Borders, etc.)