I think your question is, would there be any benefit to having a camera that supports lower than ISO 80.
This was discussed recently on another thread which I will try to find. As I understand it, the short answer is no, the native ISO of a sensor is what it is, at its base gain setting. Not sure if there is an inherent benefit to having a sensor that goes down to ISO 25, and just trying to lower the equivalent ISO sensitivity of an existing sensor is not possible or desirable. Rather, the real question is how much dynamic range does the sensor offer. To simulate lower ISO sensitivity, you can use an ND filter, which will retain your entire dynamic range.
I might have gotten some of the analysis wrong. But hopefully interpreted your original question correctly, at least.