The only real use I can see is when you are certain that you have a "perfect" configuration (whatever that may be) for the device, you could then save it to ROM-D.
Then at a later date, when some numpty has "fiddled" with the device configuration via the "admin" login, a long press of the reset button/switch will revert the device back to the factory default with the configuration stored in the ROM-D applied "on top".