The upside of these cards is their MV of 1 and the speed of protecting your most valuable creatures and permanents
Even if you fail to use Essence Flux in this exact circumstance, one mana to save a creature from removal is a great cost that's sure to provide you with a mana advantage in most situations
#10 Wow this is very underwhelming and for $70.00
There are several options available for selling Magic cards
Acid-Spewer Dragon Ancient Brass Dragon Black Dragon Bone Devourer Bone Dragon Boneyard Scourge Brainstealer Dragon Catacomb Dragon Deathbringer Regent Ebon Dragon Ebondeath, Dracolich Feral Deathgorger Grendel, Spawn of Knull Hoarding Broodlord Junji, the Midnight Sky Kokusho, the Evening Star Malevolent Witchkite Noxious Dragon Purging Stormbrood Scavenger Regent Scourge of Nel Toth Shinryu, Transcendent Rival Skithiryx, the Blight Dragon Skithiryx, the Blight Dragon Topaz Dragon Yiazmat, Ultimate Mark
Of course, it helps that this particular Cubone card was PSA graded as a 10