A card can be valuable because it is powerful in one of these formats, especially Commander, which has a huge casual player base and constant demand for unique cards
This is why the leaves the battlefield trigger really helps because it keeps your counters in play like modular, but also counts if it is bounced, flickered, or airbent
This provides the high mana requirements needed for heavy hitters like Teferi, Hero of Dominaria or Ugin, the Spirit Dragon
Finally, Goro-Goro's ability to spawn a dragon token makes it even more potent
Then exile it.) Sorcery Wurmquake Corrupted Create an X/X green Phyrexian Wurm creature token with trample and toxic 1, where X is the amount of mana spent to cast this spell
You can play Norman Osborn early, build up some counters with connive, then transform it into a beefy, evasive Green Goblin