Not what you are used to. With "Sign in with Google" or a traditional account, the service receives an identifier tied to the rest of your digital life. Here, that link is broken by default.
Sign in with an alias, and the service does not receive your Core ID. It cannot see your KYC status or your trust score, because those attach to the Core ID rather than to your everyday activity.
Sensitive information is gated separately. Reading KYC status and trust score requires a specific sensitive-data permission that an application must request explicitly and you must grant. It is not part of ordinary profile access.
Badges are visible when you hold them. An application can check the badge type, its level and when it was issued — enough to decide what access to give you, without collecting your documents all over again.
What the app never gets: a stored password. There isn't one. Your credential is device-based and biometric-secured, held on your own hardware.
Review what you have granted in your settings at uiid.me, and revoke anything you no longer use.