Another way of looking at this question: Arithmetic rationality is shift invariant, so you don’t have to know your total balance to calculate expected values of bets. Whereas for geometric rationality, you need to know where the zero point is, since it’s not shift invariant.
Another way of looking at this question: Arithmetic rationality is shift invariant, so you don’t have to know your total balance to calculate expected values of bets. Whereas for geometric rationality, you need to know where the zero point is, since it’s not shift invariant.