Every person has to decide what it means to them to use a knife. If you buy an exotic PM2 and it goes up in value, and collectors are clamoring for it, do you go ahead and use it or do you make a collector happy by putting it on the market and buying a less exotic PM2 to carry and use? Of course you paid for the knife so you are fully within your rights to use it. I think a man who makes expensive bowie's would be very happy to see one of his clients take the knife out and use it on a hunting trip.
I bought one of the exclusive Spyderco Manix 2 Xl S90V knives with the intention of putting it in my EDC rotation, and I really wanted to try out the Manix 2 XL. Sometime after that my wife lost her job and I was thinking without her income maybe I should sell some of my expensive knives, and I could try to find a deal on an S30V version of the knife to carry. In my use I'm not sure how much difference I can tell between S30V and S90V. I kept the knife in its box for a long time trying to make up my mind, and finally decided since I have a birthday coming up and I won't get any other present for my birthday, I will just keep the M2XL as my birthday present to myself and start carrying it. I took it out of the box and set it on my desk in anticipation.