Hmm, interesting question. Since I don't collect vintage knives I can't really render an opinion with regards to carrying mint vintage cutlery. However, there have been posts asking about carrying very valuable/expensive knives which I think can apply to both brand new and mint condition vintage pieces. While I have a little hesitation carrying new expensive knives but do so anyway, I don't know if I would carry a vintage one.
The reason why I'm musing out loud is because of my Zippo collection, the vast majority which is locked behind glass/acrylic display cases. I would not use my metalliques, nor my titanium, nor my pin-up Zippos, some of which are quite rare. Same with my guitar and drum company advertisers. But the point is that one standard cased Zippo is identical (or nearly so) to the next, the difference is the engraved/painted/applied design or case material (Sterling, solid gold, titanium, solid copper, even steel vs. chrome plated brass). The rare metallique is the exact same lighter underneath the applique as the one banging around in my pocket right now. In most cases the value in the Zippo is in the applied artwork or advertisement, which is why a 1970's Mickey Mouse is worth $1K and a plain one from the same year is worth $20. This isn't necessarily the situation with knives.
I suppose if I had an early Case knife that was the same model as a new one I would put the vintage behind glass and use the new one. But if that early design was no longer made and that particular piece pleased me very much, I might carry it. I feel the same way about vintage watches, as I had some valuable collectors' pieces that I wore infrequently, and they ended up just sitting around as I was afraid to damage them (rare model 1960's Bulova Accutrons), they worked but are impossible to get parts for. Since I could not get any pleasure more than looking at them when taking them out of the safe, they went up for sale. In the same regard, if I owned a valuable early knife and was afraid I'd damage it by carrying it I would either put it in the safe, display it or sell it.
Going back to the carrying an expensive new knife idea, someday in the future those knives like the Case/Bose collaborations and the many beautiful custom made and limited edition knives that members here own will be worth even more money, especially if in mint condition, like a mint Scagel custom is now. So, do we even use those new, expensive knives because of their future worth?
So, the purpose of this rambling response is, "it depends". The collector market is very fickle. One Zippo that I own at one time was trading at over $1K when they appeared on that great Internet auction site. Now they are running around half that. In the last year I've acquired two that I have wanted for years and never bothered because of the high prices. Both cost me less than just one would have back in the early 2000's. Are they any less collectable, desirable or significant? I don't think so, especially since only 100 were made of one, a very small number relative to even the most collectable Zippos. Will I ever "fill 'em up and drop 'em in my pocket"? Not a chance!
Just my humble opinion as a collector of too many things...