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.
Well, I was going with the term "investment" in the context of finance, not economics. An increase in equity would be the expectation.
In economics, you're definitely right, investment does not imply any intent of a future sale.