That's a pretty irrational fear... If my money grows all the time, why wouldn't I buy stuff? I'm buying most of my Humble Bundles with Bitcoin and it's great - every time you pay less and less and by the time the next Humble Bundle is available my money has recovered itself to more than what I had before... I may have had doubts to buy some of them with another currency, but with Bitcoin it's just a no-brainer. You'll get it all back and more.