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

I'm building a system for a smaller room (need smaller bookshelves), and I did a bunch of research and some listening. I am attracted both to the Dynaudio Evoke 10's (heard locally) and the Salk Wow1 speakers (ordered and I'm waiting on them for a trial). I have a Rel 328 sub.

Here's the thing — both of those speakers are 84db sensitivity. Several people on this forum and my local dealer have remarked, "You should get a speaker that's easier to drive so you have a wider choice of power and can spend less, too."

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.,

QUESTION: What is the value in low sensitivity speakers? What do they do for your system or listening experience which make them worth the cost and effort to drive them? Has anyone run the gamut from high to low and wound up with low for a reason?

Your answers to this can help me decide if I should divorce my earlier predilections to low-sensitivity speakers (in other words, throw the Salks and Dyns overboard) and move to a more reasonable partner for a larger variety of amps. Thanks.
@andrew -- I looked long and hard at Ascend Acoustics. They have great deals and what seems like amazing speakers.

@melvinjames The goal for me would be to avoid exactly what you describe by buying enough power. My understanding was that if there’s enough "headroom" then one does *not* have to crank things up to get the response needed for engaging sound. Perhaps I had that wrong, but that’s what I thought I learned in this video: https://www.youtube.com/watch?v=th8CxTk22pY
It's really about component matching. If have decided upon a speaker system you like, then you need to match them with an amp that will drive them adequately. Conversely, if you have found an amp you like, match it with a speaker system. In other words you don't want a low powered amp driving inefficient speakers nor waste a high powered amp on high sensitivity speakers.
@aewarren Can't argue with your logic. For me, the key factor is the most revealing order-of-discovery, if you will.
I get a better sense of speakers by swapping them in and out and keeping the amp constant.
I am not sure if the experienced change would be nearly as great if I kept the speakers constant and swapped out the amps.
This latter factor is difficult because I am not sure which speakers to get yet! I need to choose them first. Then, I'll choose among a few amps for the best component fit/match.
Down the road, I can upgrade/change speakers as long as I have enough power or a fairly flexible kind of power.
OP did you watch the video ? Red cone movement is out of phase to the input and 100% distortion....