I have read about adding skim coats/feather finishes as a coating over a concrete slab that perhaps has been contaminated with carpet glue stains. Is there any other reason to use it? Neither my wood manufacturer nor the adhesive manufacturer mention these products. They just require that the concrete subfloor be clean.

It is for filling minor voids, feathering out patch jobs where the aggregate of a patch will not allow a smooth transition and covering adhesive residue's. I used it a lot doing vinyl jobs which telegraphs everything. I also use it to feather out my slc jobs.

Super! Thanks, Stephen. I should invite you to my floor installation party!