Many BRF weddings today concentrate on the bride and groom's facial expressions, interactions at the altar, as they say their vows. That would have been regarded as vulgar and intrusive in 1947. So there was less lingering on the bride. Plus, the film would have been shown overseas to people around the then Empire who had never visited Westminster Abbey nor were ever likely to. So showing the interiors of this magnificent historic building made a lot of sense.