Narrative
Take a songwriter client whose track has been on German radio for months and is racking up in Japan. Their statement shows nothing from either territory. Not a penny. The client is not unpopular abroad, they are uncollected.
PRS for Music collects efficiently in the UK, but it does not have a direct presence in every country on earth. In most foreign territories, local collection societies gather the , and getting them to hand that money over to a UK songwriter usually requires someone on the ground: a sub-publisher.
Without one, those royalties often stay exactly where they landed.