If you want art, buy art. If you want tools, buy tools.
Done well, one object may be both.
Some may appreciate the craftsmanship of Spydercos, and collect them simply for fascination of executing the craft; the collector of Spydercos may not see Ka-Bars in the same light.
But why forgoe a good fighting knife for a 'looker'?
Is the person in question actually forgoing? Many here carry Spydercos as weapons; some would like them to look nice as well.
I'd like a good 'looker'. I'd like to drop $2000 on a gorgeous, handmade, combat-worthy knife of sheer beauty - and hang it on my wall. Why? For the same reasons that I have fine Korean pottery scattered about, and Chinese calligraphy hanging on the wall: the appreciation of fine art built upon fine practicality; the pottery function as fine containers and the calligraphy conveys a fine story, yet my real pleasure derives from taking those basic functions and extending them into fine art. I would rarely, if not never, use them for their basic functions.
As for knives (or whatever) that fail to perform well in practical functions, I would have to evaluate how good an item is purely on its artistic/craftwork merits. A functioning yet poor-quality "art gun" is really a waste if the artistic aspect is not of notable quality (see any "commemorative gun" ad near the front of an NRA magazine). In some cases, the practical quality becomes irrelevant under the artistic value - consider a painting, which is purely art with no functional "tool" value...but then, a painting is not claimed to be anything other than a medium of pure art.
Wouln't you want at least one good fighting knife for self-defense if you had a dozen knives?
Practical application is something distinct from artistic value. Some people simply have no use for the practical aspect in their lives, yet they are fascinated by the artistic aspect. If a person never intends to use a knife for self-defense, they may end up collecting beautiful knives made of exotic materials or of attractive shapes, but which are not practical for actual use - in such case, the focus is simply on the art, and that the object is not useful is irrelevant.
We look at knives, even beautiful ones, and think "combat". Others may look at knives, even intentionally weapons, and think "art".
Think of it this way: many people will, upon discoving that one of us is carring a pistol, ask "is it loaded?" That such a question seems preposterous to us and yet perfectly reasonable to them shows that some think about weapons very differently.
To each their own.
(It's very late and I'm rambling. I'll shut up now.)