Yes, guns are meant to be shot, and it's your property you paid your money for and all that.
But in the same way people tell Bubba not to sporterize his rifle and instead buy a purpose-made hunting gun, one shouldn't buy an ‘investment’ gun if they want to shoot it. In this case we're not talking about a 1 of 1000 Winchester or an engraved presentation Colt that would auction for a hundred large, or a unique historical piece. The value of it as an investment (both immediately, and extrapolated out to medium- and long- term scenarios) should be weighed against its value as a more ordinary milsurp, and the ease of replacing it either with same or a shooter grade example.
The satisfaction you get from owning it in its wrapped state, and from using it to pound lead, is part of the equation. But ‘satisfaction’ don't pay the rent, so each person's response will be different.
I collect many things, and I never seek out and pay a premium for sealed items; I do often try to acquire the best, but that entails a careful hands-on examination, and sometimes test of function. However, there are people that think the outer wrapping keeping them away from their collectibles is the very pinnacle of their treasure trove. If such a person is willing to pay you that premium price, it would be foolish to refuse.