I wouldn't go so far as saying it give me "heebie-jeebies," but I also don't see the point in collecting mass market consumer items that are not and have never been rare. Probably the closest I come to ever wanting to do so is that I have a real appreciation for old computer systems. Once, I even got it in my head that I could theoretically own and run a working PDP-11. Fortunately/unfortunately, I've never had the space to properly store, much less display a collection of obsolete home computers, and I don't even want to think about the power and space requirements to actually operate a working PDP-11

So, yeah, I truly do not understand collecting Beanie Babies, Funko Pops, or fountain pens. But, I do collect coins. I find them interesting on multiple levels. I can't think of too many other hobbies that give one a good excuse to study history, economics, art, metallurgy, and more. So many things that happen involving humans and human societies also involve money and commerce. Going back to the rarity aspect, I own quite a few coins that are anywhere from quite scarce to truly rare. It also really helps that they don't take up a ton of space, either.

I don't see anything particularly maladaptive about it, except that it's a hobby that can take up arbitrarily much time and money. But, that's actually one thing I like about it: I could definitely have fun collecting coins on less than a $100/month budget, even though I actually spend quite a bit more than that on it. The acquisition process is fun as well. I like going to coin shops and coin shows. Buying online or at auction is slightly less fun, but it gives me a greater opportunity to find what I'm really looking for. When dealing with things that are, as I said, fairly scarce, the hunt itself becomes part of the enjoyment.