Hmmmm - If it was a rare "collectable" one-of-a-kind, I'd be inclined to not shoot it, as it's value goes beyond it's basic attributes as a firearm. OTOH, I do believe that you can enjoy it as a firearm and still keep it nice. Afterall, once you get past basic functional soundness, the measure of the machine is the pleasure it gives you to operate it.
I thoroughly enjoy all the pictures of 'nice' firearms that are posted here, and while improved sights, grips, etc. do add to their usefulness, they also add personalization. I like wood furniture on my handguns, and I like to keep 'em clean, and I have a 'picnic' gun or two, though my carry guns are fairly plain. If cosmetic (and functional) enhancements add to your enjoyment, go for it!