Also, why can't I set a phantom/virtual/dummy profile for a specific app/service asking for permissions? Why do I have to choose between not using something and

Also, why can't I set a phantom/virtual/dummy profile for a specific app/service asking for permissions? Why do I have to choose between not using something and giving it access to everything it wants? Why can't I choose which real data it's allowed to see and which is dummy data, regardless of permissions?