micque, I did actually have a problem with restoring a snapshot when I was experimenting with a dev image, but that was just a fluke. I was later able to restore everything back as it was on the said dev image after a second try. I think something just got borked from my impatience, but I trust the snapshots. 
On a happy side note, I am currently running hassio on hassos off of an ssd successfully. Yes, you read that right, hassos without an sd card! I’m posting about that here:
This method doesn’t replace the OP’s method, but it is better suited for hass newbs who would otherwise just do the officially recommended user friendly hassos sd card thing. It doesn’t expose the same capabilities as running hassio in docker under raspbian, but it does allow hassos users to get away from relying on sd cards without having to rely on scripts, terminal commands, or maintaining raspbian. The devs are looking to include hassos USB boot in the coming release. I bet in the near future hassos on pi + USBssd will become the new officially recommended setup.