The World Bank publication underlines the fact that gold is the only financial asset without counterparty risk, and due to its scarcity relative to fiat currencies its price in the long run always increases.

Central banks that own gold for an extended period can reap the benefits of their gold revaluation account without having to sell any gold.

https://www.zerohedge.com/commodities/world-bank-report-highlights-advantage-central-bank-gold-revaluation-accounts

AND

GOLD INVESTING HANDBOOK FOR ASSET MANAGERS

https://documents1.worldbank.org/curated/en/099610302282427760/pdf/IDU136aee178198b114722197d515b4a9f9ef84a.pdf