Why doesn't UIView.animate(...) work with annotation on mapkit

Question

I am trying to create some annotations and spread them out from an annotation in center of them. I looked for similar behavior and came across this which is supposed to do the same from a cluster of annotations. But I can't get the animation to work. I just see the annotation at the last point, no animation!

It would be great if someone can point out why don't I see the animation?

Here's my code that is supposed to create a new annotation and spread it out upon tap on the center annotation:

 func mapView(_ mapView: MKMapView, didSelect view: MKAnnotationView) {

        self.mapTab?.setCenter((view.annotation?.coordinate)!, animated: true)
            let crd = CLLocationCoordinate2DMake((view.annotation?.coordinate.latitude)!, (view.annotation?.coordinate.longitude)!)
            var mrk = Marker(title: "", subt: "", coordinate: crd, mrkID: "test")
        self.mapTab?.addAnnotation(mrk)

        UIView.animate(withDuration: 2, animations: {
            mrk.coordinate = CLLocationCoordinate2D(latitude: (view.annotation?.coordinate.latitude)!+0.0004, longitude: (view.annotation?.coordinate.longitude)!+0.0004)
        })
    }