It sounds like this method is I/O intensive as you are writing the complete image at every backup time. Theoretically, it could be problematic when dealing with large backups in terms of speed, hardware longevity, and write errors, and I am not sure how you would recover from such errors without also storing the first image. (Or I might be misunderstanding your idea. It is not my area.)
You can see in step 2 and 3 that no full copy is written every time. It's only move operations to create the delta, and copy of new or changes files, so quite minimal on IO.
