Is powerfull Amps only for low sensitivity speakes?

This "more power is better" jazz is pretty sophomoric advice. Watts are practically irrelevant. The two questions one needs answers to are "Does my speaker need a current source or voltage source?" and "How far are you listening?" Benign, high impedance loads tend to do better with amps that provide disciplined current. Reactive, low impedance loads do better with voltage sources using some feedback. Then you have to consider the behavior of the topology and class. It’s WAY more complicated than watts.

Uh.... That sounds completely typical of a transformer coupled valve amp compared to just about any solid state DC coupled amp. Hardly a revelation, and NOT to the credit of 500 watts. 

Man... A bunch of you talk like you're actually using half of what your 500 watt amp makes. Are you using 75dB/V/M speakers? Here I am shaking my chair with a pair if 90dB/V/M speakers and a 30 watt amp without clipping it. I don't know what I'd ever do with 100 watts. That seems like an insane amount of power to me. 

@willemj 
Just crunched the numbers on that. My 30 watt amp is EASILY capable of delivering those kinds of impulses into a 4 ohm load to produce nearly 107dB. So.... What's the need for 500 watts? 

@willemj 
I based those numbers on what I'm sitting here dealing with in my condo. 90dB/V/M speakers about 12 feet away with usual boundary and coupling factors. I picked 4 ohm instead of the nominal 8 ohm rating Focal claims just for fun and it probably is more realistic. The F5 transitions out of class A into 4 ohm at 31 watts and easily carries the 24.5V and 6.1 amp to make for 150 watt transients. Looking around here, 12 feet seems a fairly average distance and 90dB sensitivity is pretty average sensitivity.