This is a great thread, thanks for starting the conversation!
I like the look of the gabion as well. The thermal mass would be awesome for storing heat or cool.
Thinking through two issues I can see with it would be structural integrity with larger bin sizes, so would smaller ones have greater support? Maybe adding reinforcing wire at multiple points in the center of each bin to keep from bulging out, especially around the bottom course?
Another potential issue would be air transmission due to the spaces between the larger aggregate. Depending on the climate this could be beneficial or a detractor. Installing an air barrier material in the wall below your exterior surface or interior surface finishes may be helpful.
Good luck!