User2288 Hi there. You're misunderstanding what's happening here.
Apps can use system capture intents instead of directly requesting access to the camera. This is in fact the more private approach to doing things.
When you press the camera button, what happens is that your system camera app (on GrapheneOS this will always be GrapheneOS Camera) opens, and you can snap a picture. Until you snap and approve that picture, the app doesn't have access to anything. You're taking the photo with your camera app, and it's the only one having access until you pass the end result to the app.
This is similar to how apps can tell the file manager to open so that you can select a file to pass through to an app. It doesn't mean that the app has access to everything you see in your file manager except for the file you select through it to pass to the app.
Both of those approaches are superior to granting an app files/camera permissions.