How do physical bitcoins work?

Could you elaborate on the mechanics of physical bitcoins? I understand they are representations of digital currencies, but how do they actually function in a practical sense? Do they have any value beyond their novelty? Are they accepted as payment methods, and if so, how do the transactions get processed? Are there any specific challenges or limitations associated with using physical bitcoins compared to digital currencies? It seems intriguing, but I'm curious to know more about their actual usability and functionality.