Never heard of passkey before. By searching it on Google, it pointed me to a passkey website it seems it's a Web3 wallet, and according to them, it doesn't generate a seed phrase, no browser extension, no email verification is required, and any biometrics are supported.
They claimed it is self-custody, but I do not believe it is any safer than using a seed phrase to generate a wallet, and the sad part is that that wallet is currently in demo mode.
Anyway, I tried the wallet it still requires email with no verification, and it only asks for your phone biometrics or pin/password to generate the wallet.