This article doesn't begin to correctly explain the usual technology for quantum dot LCD displays, or if there's actually anything different about Samsung's version, now that they're calling it QLED rather than the previous names. Samsung called them Nanocrystal displays when they first came out, then Quantum Dot, and now QLED, but it's all essentially refinements of the same thing.
The regular LED-backlit LCD displays use a white LED backlight. Of course, there isn't any actual white LED, so these are often blue LEDs with a yellow phosphor. That delivers white, more or less, but it's not as wide spectrum as you'd get from most other light sources.
Quantum dots are intersting because they have artificial band gaps -- the constrained size of the particle accurately defines the band gap, and thus, the light that they'll emit when excited by some other source of energy. In the case of QD-LED displays of all kinds, they use a blue LED as a backlight (you need a higher energy source to excite the quantum dot), then precisely calibrated red and green quantum dots, which work together to deliver a wide spectrum, pure white backlight.
Certainly other things could be done with quantum dots and displays, but no one's building an all-LED display after the fashion of OLED, one LED per subpixel, as the name implies. That's in the lab today perhaps, not at Best Buy. The stated improvements for the 2017 Samsungs in the display itself is a brighter backlight and some tweaks to the quantum dot material.