In general you shouldn’t - Netflix[0] really should get proper invite-based family sharing, and Spotify’s subscriber agreement has a section that defines Premium as a “Single-user Paid Subscription” and thus can’t be used by multiple people, legally (and you might be at risk of getting banned if they detect it)

However, passkeys can and are available to be shared via password managers. They’re not locked to the secure chip on the device where they live usually. iOS’ Passwords app has a share button and 1Password lets you share passkey-containing items.

In fact, the QR code login feature makes it even easier to do a one-time sign in to your account for a friend, if you don’t want them to be able to login to your account indefinitely.

0: Netflix doesn’t support passkeys because their main audience is people signing in via smart TVs and whatnot, which largely don’t support CTAP or Webauthn in general)