"public int Id" should fail the code review, but "public readonly int Id" should not...
public readonly int Id is perfectly fine until the property would actually be needed. The nice thing about properties is that when changing a public field "public readonly int Id" to a property "public int Id { ... }" you don't require any change of calling code. This is really the main benefit of properties over get/set methods.
Now: getters and setters are very useful once you need them. And you don't need them until you do. But there are many good reasons for them: invariants/validation and interfaces are probably the most common.
public readonly int Id is perfectly fine until the property would actually be needed. The nice thing about properties is that when changing a public field "public readonly int Id" to a property "public int Id { ... }" you don't require any change of calling code. This is really the main benefit of properties over get/set methods.
Now: getters and setters are very useful once you need them. And you don't need them until you do. But there are many good reasons for them: invariants/validation and interfaces are probably the most common.