This question establishes that there are physical bitcoins that can be bought and I recently just bought a physical Dogecoin as a trinket but I can't help but wonder if there's a solid value related to these coins.
Bitcoins can be found for 1, 10, and 25 BTC and I just bought my Dogecoin coin for 10 USD (18947 Doge after shipping and handling). If someone were to hold onto these coins for years and attempt to sell later on, what would they be worth? Is a 1 BTC coin always worth 1 BTC or, like a collectible, is it only guaranteed to be worth what somebody will pay for it?
I know it's not officially backed or anything, but is it reasonable to think that if I bought it for 1 BTC that somebody else would pay me 1 BTC for it later even if the value of BTC changes?