Non-volatility is the point, otherwise I wouldn’t be using FRAM.
I like old computers, PDP-8/i or 8/E, and PDP-11s in particular. There’s a number of things done that would otherwise be impossible if it wasn’t for the non-volatility of the core memory.
The registers in the Z80 are volatile of course so there’s a bit of logic on the system supervisor that when the power is cut it saves the state and restores it when power is turned on before releasing it to run on it’s own. It’s a system you can turn off and when you turn it back on it’s right where you left off.
It’s just an experiment in using non-volatile memory spaces and what adjustments will be needed to make it work at the architecture level. The RC2014 was just a convenient test subject.