They’re something truly unique, because baked into their design is the requirement that they be unphishable. And the only way you can have something that’s completely resistant to phishing is to make it impossible for a person to provide that data to someone else (via copying and pasting, uploading, etc.). That you can’t export a passkey in a way that another tool or system can import and use it is a feature, not a bug or design flaw. And it’s a critical feature, if we’re going to put an end to security threats associated with phishing and data breaches.