The point of backup and restore is to transfer data from one database to another while updating all the relational links. That seems to be very closely related to what we are trying to do here.
Yes building something from scratch that only supports a few Moodle features would be easier to get working at first, but then you would have to write code for every Moodle plugin you want to support. On the other hand, every Moodle plugin that stores data already implements backup and restore.
So, I think my proposal has more merit than you give it credit for.