Yes, I thought the main benefit was replacing room (with variable humidity) with very dry argon. I flush my QHY9 body as described by marc before extended mutli-night imaging sessions (e.g. astrofest). Most modern cameras are designed to avoid frosting of humidity with enclosed sensor chambers and/or mild heating around the front chamber glass.
However the QHY9 still rarely manages to get minor frosting on dust particles in my experience affecting flat correction etc. You can warm the camera, wait, then recool very slowly but not the sort of thing that is fun to be doing in the middle of a nice dark clear night
Peter has posted some good info on argon purging before and my chip in.