Signing a message with a private key to demonstrate ownership of the UTXO(s) at a particular address is a cool part of Bitcoin that is occasionally talked about, but that is largely unavailable to non-technical Bitcoiners.
Even though a number of wallets have include this functionality (eg Sparrow, Electrum, Blue Wallet, Jade), it's not always easy to do or accessible to the average Bitcoiner.
I really like how Hoseki is thinking about this flow.
Message signing is native Bitcoin functionality, but it's not something most people have ever done. It's an unfamiliar flow involving a physical device, technical concepts, and screens that don't always feel connected to each other.