Interesting. Are they worth those prices?

U.S. Mint
https://www.usmint.gov/learn/c.../greatest-generation

It's a guarantee that their values will appreciate.

Maybe to some, but the premiums are way high for my taste. Limited mintage should pay that back in the long term though.

The British Royal Mint also made one. Available at SD Bullion

https://sdbullion.com/royal-mint