In this paper we show from theoretical considerations that within the validity limits of the steady state Collisional-Radiative model the following statements hold true: (i) the populations of the most abundant charge states are almost unaffected by non-Maxwellian electron energy distributions in the plasma, whereas the populations of rare species are strongly affected; (ii) bulk or thermodynamic properties of the plasma are almost unaffected by non-Maxwellian effects; and (iii) bound-bound or free-bound emission/absorption spectra of rare species are strongly influenced by non-Maxwellian distributions in a plasma. We have carried out a literature survey to show that recent computational and experimental studies confirm these conclusions.