Passkey v password can anyone explain why passkeys are better?

[Pippick]

I read that the National Cyber Security Centre (NCSC), is recommending use of passkeys rather than passwords. I've noticed a lot of apps, websites and banks are using them but I can't for the life of me understand how they are more secure.
With passwords I have a different one for everything but a passkey is simple the PIN for my device whether phone or laptop. So if you know that you can get in everywhere?

No, it will be a key generated by your phone that you don’t see. Random, different key for each site / app for which a passkey is required.

So you can’t be persuaded to give it away to scammers.

(And as you won’t have to try to remember all the passwords you’ve invented, you won’t scribble them down on a piece of paper …)

(I heard it being discussed on BBC R4 PM this evening. And was surprised to hear this being spoken of as something new, when they’ve been a feature of my Internet use for a good few years.)