Well I'll give it a try: "Peak momentary power output" is a perfectly meaningful and useful term.
- "Peak power" refers to the maximum value of the instantaneous power waveform.
- "Average power" refers to the average value of the instantaneous power waveform (often incorrectly stated as "RMS power").
"Peak power" is easier to measure accurately and more comparable than average power, since it doesn't require a THD qualifier. The peak of a full-scale square wave and a full-scale sine wave are the same value. Average power ("RMS power") suffers from the flaw of being measured at 0.1% distortion by some people and 10% distortion by others, inflating the values.
- "Continuous power" refers to the maximum output that can be sustained long-term, limited by the rate at which heat can be removed from the amp or speaker.
- "Momentary power" refers to the maximum output that can be sustained short-term, in which heat build-up is not a concern.
Since nobody except Merzbow listens to continuous full-power waveforms, "momentary power" is actually the more musically-meaningful measurement. Real music has a crest factor of at least 6 dB, or a peak-to-average power ratio of 4, so "how loud does it get?" is determined by momentary power, not continuous power.
So, yes, if measured honestly, PMPO would be a better measurement than "continuous average sine wave power". That the value is usually pulled out of thin air does not invalidate the concept.