Betting more than the size prescribed by the Kelly criterion mathematically reduces long term capital growth and increases the risk of ruin, whereas the other individual did not. This is a classic lesson on why “overbetting Kelly” is a poor idea, even when you are confident in your edge. If you stake more than f*, the long run return in the geometric sense declines; with sufficient overbetting you arrive at a negative rate of capital growth and a high probability of ruin. Intuitively, even with a correct edge, an excessively large position size raises the chance of deep drawdowns from which recovery is difficult, and the mathematics of compounding penalises this behaviour severely.