If it is not a work of art, only precious metals and so-called gems are valuable (gems are even less likely to be mass-produced).

Therefore, if the appreciation space is limited within 100 years (with the fluctuation of precious metals, after the Expo fever, it will be weaker than precious metals. This is a precedent. You can check the souvenirs of the 1999 National Games and the earlier Beijing Asian Games). It's hard to say in 200 years.