Low-sensitivity speakers — What's special about them?

That advice — get a more efficient speaker — makes sense to me, but before I just twist with every opinion I come across (I'm a newbie, so I'm pathetically suggestible), I'd like to hear the other side. Viz.,

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Look the reason you seem to be a  bit skeptical about going towards the high sensitity speakers, is all due to 50 years of marketing ploys from The Industry.
Likea carrot ona stick we were all led down that path,, 
Look at homw many xover designs came out in the past 50 years, 
Hundreds. 
The odds of us ever comming across a  good quality high sensitivity speaker were  slim to none. 
All the audio shops jhad the box xover designs.
It too me 20 yrs to figure out that maybe xover low efficiency was not voicing my clasdsical music the wauy I REALLY wantedd to hear it. 
And so after some hesitations, I FINALLY began ordering several cheap chinese wide band speakers. 
After 4 months experiementations, pay off was nice.
It occured to me to jump  the xover ship forever.
Its takes some curiosity and guts to make this ship jumping.

I'm glad I do not ever again have to hear my classical througha  xover./low efficient speaker ever again. Its like my music is playing for the very 1st time via a  higher (91db) full range 4 inch cheapo chinese speaker. $20/pair, And you get what you pay for, = Not worth 1 cent more than $200 = Avoid all chinese full range = trash. 

When designing a driver, its a choice you make: efficiency or bandwidth.  This choice doesn't change if the driver will be used in a horn or infinite baffle,   

    

@lonemountain Your answer is so simple and logical. I suppose if some of the good stand mount speakers out there didn't try to do it all, they would be easier to drive and more easy to match with a variety of amps. It would be hard, though, for a speaker manufacturer to tell the consumer to get a sub with it if they want full bass.

Low-sensitivity some design for such have complex networks or need a small size. But in general, it means cheap low-powered magnets undersized transducers, and cabinets. It means the loudspeaker and owner of such has to purchase a massive power amplifier thus putting that speaker's cost savings back on the owner since now his amp costs more is larger and uses more energy. It also means thermal compression in most designs since amps heating VC.

The benefit if done well (like Dynaudio in general) is more bass extension from a smaller box, but you need a beefier amp than otherwise typically to be able to deliver that bass. Power needs increase exponentially with lower frequency.

Its easy to have a very efficient speaker. Just skimp on the bass extension. Most cheap speakers with limited bass extension are very efficient. THey have to be much larger to bee both efficient and have good quality extended bass.

Or just offload the bass to a powered sub or two or 4 and most any decent quality speaker can cut it.