Like most Pokmon cards, the value of Charizard VMAX depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Shining Fates Shiny Vault)
The deck featured evoking the two creatures while using cheap Feign Death spells to bring them back for a second EtB, which would end up with them staying in play to attack and block with
You could likely make Akoum Hellhound worth playing as a 1-drop in a Ziatora, the Incinerator Commander deck
To be fair, he sold the card inside a diamond-encrusted card case and necklace he displayed it in, which added to the value of the overall of the card, but $16.5 million with or without the diamonds is a hard price to swallow
That's simple enough in theory, but the problem is that it takes a while to gather ten luck counters, which gives your opponents time to take out the enchantment before you win
The next milestone is finding a few draft archetypes that they feel comfortable playing