Well like many things government supports. What's the economic return of agriculture grants, of reduced vat on building and development, of fix asset grants to business, of increasing the budget for primary school teacher training, of building a new road to the airport...
Government tries to support without there being a quantifiable return. In this case, it's all a bit muddied by the history. The fund started as a way to either fiddle vat or encourage a film industry here, or a bit of both. It's been moving towards being more of a managed investment so it's all a bit messy and confusing.
Still, I'd have thought for those who think it's a waste of time, that reducing our exposure and taking a profit is a good thing.