As @acutename mentioned, its done to increase landing efficiency.I also am curious about the last minute switch to runway 33. I know it's done, but what are the protocols for switching like was done here?
A commercial pilot on a Youtube channel mentioned that it is a routine option asked by ATC when they need to land planes quickly. He then related that he had flown the switched route and that it demands total concentration from the flight crew.
The pilot also implied that accepting the switch is voluntary as the ATC asks crews if they "can accept" the new assignment. This implies that if the flight crew is not comfortable with a rapid new assignment to a tricky approach, they can decline and still land at the originally assigned run way.