I'm a trusted trader for over 2 years now and I buy games with the steam wallet money (or paypal, but rarely) I earn from trading games for keys and then later selling them (mostly after summer/winter sales) when the prices go up again.
In the past 2 years I haven't had a single negative reputation from trading, that should mean something at least. Games won't go missing from accounts (if you mean that I buy them with stolen/forged credit cards)