I don't know why I click on DPR links anymore; I guess it's one of those social engineering tricks:
OP: Here, click this link, it's about Pentax
Me: Okay, <click>
Me: Crap, it's DPR and their dated, mid-90's navigation system
Odd, I don't think desiring a lens for it's fine craftsmanship is a "frivolous" reason at all; that's like saying wanting BMW over a Hyundai because of build quality is "frivolous".
Quote: Like all of Pentax's Limited series primes, it's also a finely crafted piece of kit which is a delight to use - a somewhat frivolous reason to choose one, perhaps, although still perfectly valid in its own way.