There are also instances where customary usage is so set that to replace one with the other becomes "odd". For example, in economic analysis,
"There is a shortage of skilled workers in the labour market."
Here the focus, as would be correct in economic analysis, is on the knowledge and training of the persons concerned.
We do not normally say,
"There is a shortage of skilful workers in the labour market." (or it would something entirely different)
Here the focus would be on their performance, and it would be absurd because it is impossible for an economist to predict aggregate individual performance. It is not his job either.