One of the biggest barriers to getting into bitcoins is the tedious process of going through several payment processors to actually get the bitcoins... Besides cash itself, the other alternative I can see would be money orders where you know that you can cash it without having to worry about check fraud and waiting for it to clear.
So, why don't more exchanges have this as an option?
Money orders, like checks and other demand instruments, are reversible (in certain circumstances), while bitcoins on the other hand, are not.
"A money order can be lost or stolen and there are procedures for reporting that. Losses could occur even weeks after the check has cleared"