Apple's opt-in is only triggered when you attempt to use a feature that relies on a function of the opt-in or when a new OS feature utilizes those functions. It's not a nag. It doesn't ask you until you want to use it. Microsoft assumes you want to use it and hides the opt-out settings under an "Advanced" button during setup when it asks about new features and then promptly asks you again after it assumes that you don't know what you're doing. The "Are you sure?" prompts on Windows are far more egregious.