As a holder of numerous BTC physicals I think the market for selling is all but dead. The value of BTC is too high to transact via traditional methods and there doesn't seem to be any demand for physicals or cold storage BTC. When I bought, I always intended to hold, and pass them on to my kids to peel. Physicals are a conundrum because they have a higher BTC premium the lower the fiat value, so you'll never recoup your BTC, and most have realized that. I spent 17btc for a Cas 10, and so on, so would have been better off just saving the BTC on paper wallet for my kids, but I"m damn glad to have the Cas 10 and there are no regrets.
msin brings up an interesting point. Bitcoin demand has far outpaced demand for physical bitcoins, and basically any other investment for that matter over the life of bitcoin. Trezor used to sell wallets for 3 BTC. Pizza sold for 10,000 BTC. Alpaca socks, etc etc.
Everything has lost basically 99% of its value vs BTC over the years. Everything EXCEPT Bitcoin collectibles. Physical bitcoin collectibles have retained more bitcoin value than any other item over the last 11 years that you could have purchased with bitcoin. msin spent 17btc for a Cas 10, but it is still worth over 10 btc. If he had purchased anything else other than a physical bitcoin collectible it would likely be worth close to zero in BTC. Physical bitcoin collectibles are also a great way to force HODL.