A) The name sounds like a 90s boy band.
B) The marketing seems bunk. I find it hard to believe you can trick a plant into thinking "winter is coming" based on nutes alone (vs. temp / lighting triggers), compared to a normal "you're just getting old and dying" feed schedule.
C) It looks to be a standard "no nitrogen / P and K only" bloom formulation, and it's used in their feed schedule with other P-K only products for the last week. Nitrogen is used in chlorophyll production, and coloring is typically achieved through a reduction in chlorophyll to enhance a strain's natural pigments.
D) The pigments are classified as flavonoids, which are produced in trichomes along with terpenes and cannabinoids. Flavonoids can have some therapeutic effects themselves, but are typically such a low percentage that they're ignored.
E) Any strain will have natural colors that can be enhanced based on its genetics. Typical "very purple" strains tend to be lower in THC, but they are popular for bag appeal, as you mentioned.
So, yes - technically, you are affecting bud quality somewhat, but not really increasing potency / THCA (which is the quality most are concerned with). And, you could probably achieve the same effects with any standard feed regimen that cuts nitrogen earlier. I would save your money and just follow whatever typical low nitrogen bloom schedule that you normally would.