Being the scale of Amazon has nothing to do with whether or not fault-tolerance is important to an application. In fact, amazon has far fewer real needs for fault-tolerance than many other businesses (its a retail site!).
You should use embedded mode if you do not require fault-tolerance and can miss updates. Otherwise, don't. Regardless of scale.
You should use embedded mode if you do not require fault-tolerance and can miss updates. Otherwise, don't. Regardless of scale.