[dchest]

Nothing in this post is specific to passkeys; it reads like advice to not encrypt data. There’s no way to prevent some users from losing their encryption key anyway. Whatever warnings you include, even when software doesn't connect to the internet and just encrypts local files, someone will write to support that they forgot their password and ask you to "reset" it.

Good advice at the end, though.

[shepherdjerred]

The issue I think is that passkey managers don’t make it clear that deleting a passkey can cause permanent data loss

[pmontra]

Because passkey managers have no idea what a service is using its passkey for. They could warn that deleting a passkey could make all sort of bad things happen, but for most services it will be only the loss of access. What the alternative could be? "Before deleting this passkey you must contact this site and ask them what data you will loose. I give you a week. Come back here a week from now and confirm your desire to delete this passkey. I will not make you delete it before that day. See you!"

[orbital-decay]

There's a big difference between being kept in the dark and being informed but careless.