Some revolving door systems (not the ones you mean, probably) actually improve a lot on the classic turnstiles or gates.
They allow one authorized person to pass from one side through but sensors on both sides can easily detect if another person is trying to piggy back from the other side of the door. And there's no way over or around them. In higher security environments where unauthorized persons getting on the other side of the door is already an unacceptable risk they can also allow security personnel to trap someone in the door (rotate only 90 degrees).
And as far as usability and efficiency goes, they can allow traffic both ways at the same time (as long as both people are authorized).
