The first time I got asked by a site if I wanted to use a passkey I immediately googled what they were and... never really found the answer, not in the 5mins I devoted to being distracting from my task at hand anyway.
"magic fairy dust to login to apps." is the most accurate description I've seen.
Unlike a password or a TOTP token, I know how those work, I know its my responsibility to keep track of them. If my passkey is on my phone what happens if I lose my phone? Do I need a unique passkey per device? How do I rotate them? What if a device gets stolen?
I'm so glad I'm not alone in thinking these are so poorly explained.