They are not more secure from a cryptographic standpoint. There are different attack vectors and for some passkeys are superior but in others they are certainly not.

Additionally, part of the security concern is also accessibility by yourself.

edit: Just tried the Google passkeys on one of my Android phones. It is a complete usability hell and it seems I cannot opt out again without logging in from my browser and deleting my "device". If there is another way to just do it from my device without an additional browser, please tell.