To be even more pedantic, there's nothing stopping you from using VMDK (or other disk images like VDI, VHD, raw/dd, etc) files as a container (like tar or zip),

To be even more pedantic, there's nothing stopping you from using VMDK (or other disk images like VDI, VHD, raw/dd, etc) files as a container (like tar or zip), other than some extra overhead. They can easily integrate into your desktop environment, possibly even easier since there's probably more support for mounting disk images than there is for mounting archives...