Immortal monsters, regardless of ATK, can move in and out of Crush Terrain freely, gain Terrain Bonus on it, and when destroyed by battle, turn the surrounding spaces into Crush Terrain, often destroying the attacking monster
It also makes all your 1 Strength characters with high Willpower much more threatening
What makes this Traveling Chocobo several at least $3000 more expensive than the others on this list, is the fact that its a Japanese exclusive, while being incredibly rare to begin with only giving it more appeal in value
Thrakkus is a full 2 mana cheaper than Atarka, too
Bold Embossed Charizard Cover: Charizard mid-flame, pressed deep into the leather
In order to check how well you understand the system of priorities, try to analyze what happens at which moment in the sequence of Bituminous Blast, Bloodbraid elf off Cascade, Act of Treason off Cascade