Contrary to my other post, which was more educational than practical, yes, you generally would not back up app data via a hypervisor snapshot. Generally you would only backup the OS disk and perhaps the application binaries. This would be for quick restore of the OS and app, so you don't have to spend hours reconfiguring your OS. (especially Windows based OSes....) I also do an IN OS backup as well, for individual file restores in the instances you accidentally destroy something in /etc for example.