I have read wikipedia about kelly criterion but i dont really get how much bigger the risk is when using kelly 2% instead 1%. I mean doesnt it mean for JD that at kelly 1% 1% of the house can be won. I see JD is only at 0.5% what is even below the optimum kelly describes. But even with 2%... its a percent value... the house cant really be beaten this way or am i wrong? It can go down very much but each new bet with max win of the house 2% means the house will be less than before... so the max win will be less then. If it would be a fixed value then of course... at 2% the house could be beaten in 50 wins. Which sounds like it will happen very rare. But its not even a fixed value. Its a percent value. That means you cant win back the losses as fast as you could with fixed values but the same goes with the losses. They will slow down. I dont see yet why 2% should be so much worse than 1%.

Aha - so it does use a PIN although I am guessing that the PIN is being typed in on the PC (so is vulnerable to key logging).

I think if the PIN were to be entered into the device directly (i.e. no chance of key logging) then it would be a much better (although requiring at least a numeric keypad - a more expensive) solution.