You can't "disable" 120Hz. A 120Hz TV always operates at 120Hz. You can adjust it, however.
In my experience of selling TVs, in larger sizes, (eg: 55"+), 240Hz definitely helps. In larger sets, sample-and-hold blur inherent to LCDs is more readily noticeable and IMO 240Hz sets remedy this better than 120Hz ones do. Reading reviews you will often read that on most 120Hz sets motion resolution averages somewhere between 600-700 lines out of a 1080 image, generally 240Hz sets can resolve the full 1,080. Whether that is noticeable depends on your eyes and the size of display, but it is definitely measurable.
Again, articles like the one you linked from PCMag make me shake my head because they 1) tend to oversimplify things, and 2) quite frankly, the author doesn't really know what the hell he's talking about. E.G. he refers to the 600Hz subfield refresh of a plasma as "downright overkill," when in reality that number actually has nothing to do with the real effective refresh rate of a plasma, which, by the way, is still 60Hz. The refresh of a plasma and the 120/240 you find on an LCD is something entirely different.
Also, blur reduction and frame interpolation are not mutually exclusive. (On most sets) you can independently adjust blur reduction (frame repetition) and judder reduction (interpolation/smoothing).
ht Panasonic 60" ZT60, Monitor Audio: Silver RX6, RX Centre, RX1; Martinlogan Dynamo 700, Marantz SR5006, PS3, Oppo BDP-103D, Panamax M-5100PM
2ch Sony 32" W650A, Sonus faber Toy Monitor, REL T3, Marantz PM8004, Sony BDP-S1000ES, JVC T-X3 tuner, Apple TV, Peachtree Audio DAC•iT, Panamax MR4300
pc Monitor Audio Radius 90HD, Audioengine D1, FiiO A1
+ Sony 65" XBRX850B, Sony BDP-S5100