At the moment any bet which is more than 50USD will take 1 confirmation, then 2 confirmations for 200USD+ and an additional confirmation for every 300 from there, up to a maximum of 4 confirmations.
Maybe it would make more sense to allow players to keep a balance "on site" so they can play in real time. If I was playing with large amounts of money I'd for sure want to know which spin my bet was riding on before the spin happened.