Basically: get a load of money from extractives ➡️ less opportunity cost / store of wealth / macro issues ➡️ sovereign wealth fund 🤑 If you borrow / save money to crowd in private investment that’s a different beast (article calls this a strategic fund which I think is a more useful term)

You can see the problems in the comments - opportunity cost vs paying down debt - different set of issues re: prioritisation of investments - overlap with loads of existing bodies (green investment bank, anyone?)