Quote - So it came to light through your discussions that this is probably just an amusement - not particularly a useful simplification except for a clay or dirt shader. And so that's all it is. An interesting curiosity - a simplfication that has only a limited set of circumstances in which it applies.

Well, I've actually implemented this curiosity: 1, it works, 2. saves me a node, 3. exercises the bean. Thanks.

Quote - But the more important thing is to become comfortable manipulating algebra to draw conclusions about how to build shaders. In that regard, this is a very good "etude".

There were a few obscurities (to me) that prevented the abstraction that would have made the exercise work for me. No question it was neat and did sort-of make me look at what is happening differently - we are still feeding diffuse()/Poser linear information, right? not fixing the diffuse() node? - but those core concepts that cobaltdream finally clarified to this difficult-to-penetrate grey matter haven't moved much.

A bit OT, but I still can't reconcile the concept that if Poser needs linear information to process colours correctly and only the fewest are giving Poser that due to ignorance or apathy or expecting Poser to do the right thing with colours, why has it been left this way? IOW, why doesn't the diffuse component do GC internally, instead of allowing the entire bloody Poser community to produce rubbish? I see so much yellow bloom in the galleries it's sickening: yes, I know the information is available here, but jeez, some artists don't even go in here.
So, it's not getting out there. Sorry, but I have an issue with that. GC is not a Pro feature if people unwittingly produce crap because they don't understand they actually need to compensate for a Poser shortcoming with extra nodes in the material room. If GC were part of the process by default, lights would be designed around it and people would be producing better renders "out-of-the-box".

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks