Modern system builds are typically deployed dynamically, so one build can accommodate multiple hardware platforms using scripts to determine what action to run depending on the platform, MDT and SCCM and two Microsoft solutions that allow this. The required software/applications can also dynamically deployed in a similar fashion. So a system can be rebuilt quickly and effectively without dozens of disk images.
You system image would take up a lot of space and only be of any use to you and that device.
Again, typically all your userdata would be stored on network storage (SAN or NAS) so this would not be captured by a system image.
These may be reasons that a system image is valueless in your instance.
What exactly is the critical data you want to be backed up?
Ensuring that data is backed up may be all that is required and should your device need to be rebuilt that can be accommodated without a system image.