It's not being used "in lieu" of anything. it's being used to connect to the GE.
I understand that. But the requirement requires, essentially, the nearest of either the water supply or building steel electrodes when available, and preferably in the area of the SDS.
Say, for instance, there is structural steel somewhat near the SDS, but very difficult to route a GEC. I can see someone choosing to run a combo GEC/wire-type EGC with the primary CCC's "in lieu of" a solo EGC just because it is easier than running a GEC to the nearest structural steel... especially when planning on, having to run a wire-type EGC with the primary CCC's.
What possible beneficial purpurse could such a change make? Do the people that think these things up not realize how many bazillion SDS's there are out there? Especially small transformers under 10kVA?
I hope you're asking for opinions from any(all) forum participant(s), 'cause I see none. The only thing I can possibly think of is that some may consider a dubbed "EGC" as allowed to be undersized compared to a GEC. There was at least one countering comment that got shot down with little explanation.