There is always, always, a subtext of "if you don't wish to cooperate, I may need to exercise my discretion to ...", with the ellipsis being anything from literally tearing your car apart in a "reasonable suspicion" drug search, to some made-up traffic infraction, to anything else that police are trained to use as coercion.
Just because you have some theoretical rights that a judge may at some point months later grant you, doesn't mean the officer can't violate the hell out of you right now and probably get away with it - and end up getting a baseless conviction, or a paper trail in police records, or just make you late for your job interview.