I just point out that it is as safe as handing over your cash to a complete stranger and hoping that they are still there to give it back to you in the future when you ask for it.
How can one engage in online money transfers without involving strangers at some point in the transaction?
In my mind, there's a big difference between "
Here's the few bitcoins you are requesting in exchange for the product/service that you are offering." and "
Here are all my bitcoins, please hold on to them for me for free. In the future when I ask, please return them to me or send them where I request."
Perhaps others don't see much of a difference there. Even so, why increase your risk unnecessarily. You already have a certain amount of risk in the transaction with the merchant, why increase that risk by using a wallet that requires you to give up control of your money?