Look, I'm a very technical person and I prefer long, auto-generated passwords stored in a password manager. It's stupidly simple, works with every service and I can hand-enter my passwords even on the most obnoxious smart TV set.
I get that Passkeys do that in a more convenient way and prevent regular users from reusing simple passwords. So far, so good.
But I also use several devices over several different ecosystems and like the syncing my password manager gives me. I even sync my TOTP 2FA codes. I also like being able to make backups of such important data.
I don't want to loose access to a service because I lost my phone. I don't want to go to the settings of #M services and add my #N devices. That is a LOT of work for very little benefit! And I need to go through that hassle again every time I get a new phone or tablet or laptop or desktop or smartwatch (?) or authenticator device.
Yes, some password managers like bitwarden also do passkeys and sync them. But I would still have to figure out which services use it. And then I am locked into my current password manager.