From what I got on the last Corona 7 webinar at 10:58, clear coat absorption could also be used as a “stain” parameter to completely alter the color of wood materials without having to use new textures or color correction node.
So I could start with a basic natural wood texture and then play with the absorption parameter to find the right stain color. Is that one of the intended used for this parameter?
Yes 
For me it’s debatable how long it’s still physically sound as dyes and stains are quite penetrative as opposed to lacquers, the latter being more fitting to be simulated by clear-coat.
Also, since most lacquered woods are both (or all three) dyed/stained and lacquered, the Physical Material would need multiple clearcoats and definable thickness (Maxwell had that kind of shader), so with CoronaPhysical having just single, you would have to go to CoronaLayered material again.
This would be well worth the research.
You can also refer to the following discussion as some things are explained in more detail with some free samples. https://forum.corona-renderer.com/ New Corona Physical Material (PBR) playground! #msg189217
“Clearcoat” as a separate I/O material/shader would have made it possible to create such kind of multi-cotaed materials. Especially, if it also featured various layering options.
ie.
LuxCore’s “Glossy Coating” material
Glossy coating is an “empty gloss coating” material. It is used to add gloss layers on top of other materials. It is something of a special glossy material that has no base reflector of its own, but rather takes another material node as its base.
Yup, some new material systems like the latest one from Disney is based fully on layering. There is no base materials and layered material anymore. Everything is a layer.
I tested it with existing way anyway, and it’s pretty cool way to do wood :- ).
