Depends strongly on the situation. It's true that where heating would be used, if mounted in such a way that all that heat is available (ie, not recessed into

Depends strongly on the situation. It's true that where heating would be used, if mounted in such a way that all that heat is available (ie, not recessed into a ceiling fixture), the 97% is useful. (But not necessarily maximally efficient, because if you wanted heat in the first place you'd be better off not turning your energy into electricity, a process with ~50% efficiency at the power plant, and then incurring further distribution losses.) On the other hand, if cooling would be used, it's even less efficient because now you have to cool away all those 97%.