Why do some buy a Vacheron Constantin or a Patek Philippe when an Omega speedmaster would be more reasonable and every bit as technically desirable? ( And why do I wear a Vostok K-39 ? )
To feel special, above the plebs. (Don't know. O_o Why do you wear the Vostok? I wear a Bering Titanium.)
The need to feel special seems indeed a possibility when it comes to watches...
Aside from the fact I feel uncomfortable with battery-powered watches, because it is affordable and because its dual time function is nice to have when you have to deal with contacts in another timezone.
To come back to computers and CPUs, The situation is actually the same as for the i7 6950X ( or as it was 6 years ago with the i7 990X ) : one has to admit that there is a not so small niche that needs or can make better use of this kind of CPUs, just between the professional multi CPU systems and the enthusiast retail segment . Although some may be suspicious about the TDP for instance....
On the top of that, there is a tendency for thisniche to bleed into the enthisiast segment itsef , call it wealth effect , luxury effect or pice insensitivity or simply human drive to bigger / better things. And Intel knows how to make best use of that ....( that's why the i9 is such a nice move rather than sticking to i7 extreme On top of creating a segment to capture those willing to pay for that, it makes the masses more comfy with buying an i7 rather than an i5, because the i7 now looks rational ! )
The same with laptops, where there is a market for high end overpriced gaming laptops.
If such choices are aligned with the financial situation of the buyers, it's not to be critised per se. Let them be happy with their purchase. Even if not rational as was rightly said before,.