The Doublez roulette bet is not even technically speaking, a bet. You can only make the bet if you just won something, and you want to make the same bet with double the bet. This is useful if you are using exotic roulette bets.
For example, say you win an exotic bet like a 5 chip Voisins 19, because the ball landed on 31 (a neighbor of 19). You were betting 5 dollar chips. You'd lose 4 of your bets ($20), and win one at 35 to one, ($175), leaving you with $155.
If you wanted to make the same bet again, and wanted to double it, as one often would in a roulette betting progression such as a parlay, it is much easier to ask the croupier to double your bet, then play with your winnings and try to figure it out. The croupier can do this much faster.
Max Baker - Staff Writer