I don't necessarily see the few items I own as an investment, I mostly like having them. I like displaying them (livingroom space allowing). Of course I wouldn't rule out selling some of the more limited collector's editions of video games or merch I own, but only if the value increases very, very substantially and I certainly don't plan to do so when I'm buying them.
First of all, "investment," in terms of tangible assets, does not imply an intent to sell.
Second, you can do all those things you mentioned after opening the package, provided you take care doing so and save the packaging for storage.
The only logical reason one would choose not to ever "break the seal" would be to ensure optimal appreciative gain.