The use case is a low-power device that does not use batteries but can store energy, and runs at a low and potentially-unknown duty cycle, either has no actuato

The use case is a low-power device that does not use batteries but can store energy, and runs at a low and potentially-unknown duty cycle, either has no actuators, or has actuators that have a stable latching state and where the actuator remaining latched does not present a safety or operational problem. I think that describes the use case, but besides a simple datalogger, I'm not coming up with examples of where this would be useful.