McGrath does have a point: for a person, the value of winning or losing money may not be the same as its face value. If you proverbially "put your shirt on a horse", i.e. bet with your entire existence, you are being unreasonable ("addicted") no matter what the chances. Conversely, if you need a medicine for your life but only own a fraction of its price, an unfavourable bet may be reasonable if no better one is available.