Why passkeys from Apple, Google, Microsoft may soon replace your passwords

Have been using a key since Google started requiring too much fooling around to sign in to the e-mail account. Currently, for the google account the key is required after signing in with id and password. When I was reading about which key to get and how to set it up, seemed to me the military had already initiated the use of keys.
I have to admit it is more convenient than being sent a code, via e-mail, or text, or phone call each for each sign-in at numerous websites (anything financial). Wish more websites were setup to for the use of a key. It is more convenient and more secure.