This note is concerned with the assertion of Barletta and Nield (2009a) that "a fluid with a thermal expansion coefficient greater than that of a perfect gas (beta > beta (perfect gas)) is of marginal or no interest in the framework of convection in porous media", and that for a remark of Magyari (Transp. Porous Media, 2009) about the forced convection eigenflow solutions, the circumstance beta > beta (perfect gas) does not represent "a sound physical basis". Here, it is shown, however, that these assertions are in contradiction with the experimentally measured values of beta for important technical fluids as e.g., air, nitrogen, carbon dioxide, and ammonia where, in the temperature range between -20 and +100A degrees C, just the inequality beta > beta (perfect gas) holds.