johnyj: Imagine a Roulette wheel, sometimes you win, sometime you lose but on average it all even out (well accept for 0 and 00, but lets pretend those aren't their and instead your paying 1% conversion fee at an exchange which has the same net effect). Now would any sensible merchant agree to be payed with bets on a Roulette wheel? No because you ALWAYS lose in the end, you hit a streak of losses and are eventually wiped out, business need their operating capitol if they loose it they can't make another set of products to sell just like you can't make another bet. This is why stability is key.
This game is different, the house advantage is at bitcoin side, e.g. who hold the bitcoin wins long term wise. Because the fiat is inflated all the time (now 85 billion per month) and bitcoin supply is limited, the bitcoin value will increase over time