In Japan, most forms of gambling are generally banned by the Criminal Code chapter 23; however, there are several exceptions, including betting on horse racing and certain motor sports.
Jogo is estimated at 8 or 9 fingers so Gojo should be worth at least ten fingers as he managed to overwhelm Jogo's territory with his own. Given that neither element inherently counters the other, I assume that the expansion battle is based on amount of cursed energy.
Jogo is one of four cursed spirits born from humanity's collective, subconscious fears. His appearance and abilities imply he was born from their collective fear of volcanic eruptions.