Is powerfull Amps only for low sensitivity speakes?

This is an interesting discussion.  My immediate query is why are there out there sensitive speakers and insensitive speakers?  I have no audio technical knowledge but I do know from reviews of speakers that apart from what they have in common in regard to most different brands, the approach to their design in some aspects are always slightly different in some way; its like the designer of each brand thinks he or she knows best how to create the perfect speaker.  However from my limited experience if one tested different speakers and amp with power (some oomph) in comparison with amp of lesser power, the amp with power will more likely show the individual 'talents' of each different speaker while the lesser power amp may not give the 'full sound' with some of the speakers.   

Mine are low-mid 90’s I think as far as sensitivity. 
I run them with McCormack dna-750’s. 
Only rated at 250W. But boy oh boy do they sound sweeeeet, nary a hint of distortion anywhere with my CD player. 
Never a chance of clipping, and the peaks and crashes, double bass is flawless and tight. 

One other thing to consider:
With many manufacturers, in a line of variably-priced items (in this case, amplifiers), as the designers have more money to work with, they often times put higher quality or performance in the higher priced items.  With power amps, the high powered ones, which command a higher price sometimes have better performance or features.
Back in the day (over 30 years ago), I'd say that many of the then high-powered amps did not sound that good at much lower power levels.  But I think that's a thing of the past.  I suspect that most "class a/b" amps today run in "class a" up to a watt or two; if you have efficient speakers, might be listening in "class a" much of the time.

I am running Wilson Maxx 3 speakers (91db) using D'Agostino Progression monoblocks. Rated at 500 watts @ 8,1000 watts @4, and 2000 @ 2 ohms. I am very happy with the combo. I now understand what "headroom" actually is. The learning curve was quick as I found out that volume levels were not the same as when using a borrowed pair of ARC Ref 250 SE amps. I am amazed when listening to classical discs. The dynamics at peaks are amazing. Every note is clean and in its proper space in the recording.

I am running Wilson Maxx 3 speakers (91db) using D’Agostino Progression.
The learning curve was quick as I found out that volume levels were not the same as when using a borrowed pair of ARC Ref 250 SE amps.
I am amazed when listening to classical discs. The dynamics at peaks are amazing. Every note is clean and in its proper space in the recording.

It’s not about the wattage ratings of both, that’s because the D’Ago’s have far better/more current delivery into low impedance’s than the ARC could give, which will give you the full dynamic impact of transients, also giving you more "space" between the notes, the ARC would sag a little and sound a little compressed with these transients compared to the Ago’s.

Not a good impedance curve for tubes, this speakers needs current. but because it’s a very nice 90db efficient an amp around 150w or more will do, but as I say one that can deliver current!
https://www.stereophile.com/images/archivesart/909WM3fig1.jpg

Cheers George