i didn't write the section and would welcome you to rewrite it.  about it, i thought two things were true: the capacity per particle of thermal energy (per degree of freedom) is proportional to absolute temperature (with the Boltzmann constant k as the constant of proportionality).  also, at least in engineering thermodynamics books, calling heat a "low grade energy" in comparison to non-random mechanical or electrical energy is common because to convert this "low grade" energy to a high grade energy, a heat engine is used and their cannot be 100% efficient.  but to convert electical or mechanical energy into heat is always 100% efficient.