Agree with @pastwise.
And ED is a different but related discussion.
I’m waiting for some school to employ the trifecta of ED + heavy WL usage + guaranteed transfer/deferred admission.
Cornell & NYU already use 2 of the 3.
@intparent: “Guessing that the WL students often have lower stats on average . . . .”
An anecdote to consider: At our high school, both of the school’s nominees for the Belk Scholarship at Davidson were waitlisted; they both applied RD. A classmate with lower GPA and test scores was admitted at Davidson; however, this student applied ED. (According to this recent article, 60% of Davidson’s admissions were through ED: https://www.washingtonpost.com/news/grade-point/wp/2016/03/31/a-college-admissions-edge-for-the-wealthy-early-decision/?hpid=hp_hp-more-top-stories_college-admissions-710am%3Ahomepage%2Fstory) Our high school’s guidance counselors say that they are seeing the waitlist used a lot more with high GPA/high test score students.
Yes. ED is related and UPenn is also famous for using that to make it look more selective.
Even schools like Harvard is not beyond playing this selectivity game. If you interview at Harvard for RD, and they ask you and you tell them you already got accepted by Stanford or other top schools for EA, you can kiss your Harvard chance goodbye unless you are an absolute must have for them.
To most schools, US News ranking is more important than actually getting the best students.
I don’t disagree that higher stats students are sometimes offered WL spots. But they are less likely to take the spot for the very reason that they were WLed to begin with – they likely have higher ranked acceptances. And they now know they likely aren’t getting merit at a school like Case even if they get in. So the pool that accepts spots on the WL often does have lower stats.
The logic is very simple. Yes, higher stats students are even unlikely to come. So put them on WL instead of wasting acceptance letters and pull down yield rate.
But some of those will end up having little other better choices just by probability. Note there are plenty of students who can beat Case’s average stats, and can’t get into the top schools.
Those higher stats who had no better choices will end up signing up on WL. So now Case knows it has much better chance in them actually coming now. It doesn’t matter how many other people sign up on WL.
So Case just filtered out the high stats without better choices from high stats with better choices, without putting out acceptances to find out. It can then offer those high stats without better choices.
And there are plenty of those to offer.
BTW, here is the exact line as in the article you quoted.
“We love our wait-list kids,” Bischoff said, noting that their academic profile is as strong or stronger than the overall entering class.
@intparent, are you saying that college adcoms are lying? I’m pretty certainly that they are not. Plenty of high-stats kids around for selective colleges (just outside the tippytop). Which is why aggressive use of the WL is pretty attractive for those schools.
What else would you expect him to say about his waitlist kids??
Another thing to keep in mind: If the practice was not beneficial to Case, they would not engage in it.
intparent, honestly, you are making worse points trying to justify the bad points made earlier. 
It would be very rare for someone to say the quality of WL students (which the school did not accept in the first place) are better than the ones already accepted. It doesn’t look good on so many levels.
The only reasons he said it are (1) that’s the truth, (2) such practice is no secret anyway for people in the admissions or who follow it. So he did not give second thought when saying it. I doubt he’s going to say it again even if you ask him to.