why on games like overwatch/wow/runescape and others like that can you not bet for fg?

both parties agree upon terms of said duel/fight, winner takes the coin. (record the fight for evidence incase someone breaks the duel terms) i bet the comunity would be so involved in this.

Betting is allowed just not supported by jsp.
Although a user can be locked for welching a bet because it's considered a scam.