Even if you never sell a knife someday they will go somewhere. IMO boxes are part of the package, in the case of CRK it's generally where one would keep the DOB card and Reeve's info along w/the the accessories. Most 'higher' end knives include some sort of swag from the manufacturer in the box, a cloth, pouch, fobs, stickers, tools, spare parts, etc. I generally never use that stuff as I have tools, hanks and cleaning supplies and don't use pouches. It all stays in the box. I have purchased knives w/out box's and I do consider it a hit to the value. The only exception for me where it really doesn't matter on a purchase is if I know it'll be a user and in that case it probably already is a user otherwise I expect the price to reflect the lack of packaging.
I've never sold a knife but do give them away occasionally and I like to have the box as part of the gift.