Are Proof Coins Real Currency?

By GovMint :

Yes, proof coins are real currency so long as they are legal tender with a face value recognized by an issuing authority, such as the United States Mint. However, their true appeal to collectors generally exceeds their nominal face value due to their special manufacturing process, limited production runs, and often pristine condition. While you technically could spend a proof coin like any other currency, doing so would be akin to using a painting as a dinner tray – it's possible, but it overlooks the item's true purpose. Proof coins are primarily produced for collectors and as commemorative pieces, not for everyday transactions. Therefore, while legal tender, the role of proof coins in the financial ecosystem is mainly symbolic and collectible rather than circulatory.

Sources: 

https://www.usmint.gov/learn/collecting-basics/glossary