The average Snapchat user isn't going to think about the process of uploading a picture to a central server which is then relayed to the intended recipients and

The average Snapchat user isn't going to think about the process of uploading a picture to a central server which is then relayed to the intended recipients and then deleted on the proprietary client-side application (which can be worked around, the problem is that third-party may retain data indefinitely). The average consumer is not that technically literate, consider the people who think Facebook = Internet.