Apps facilitating cryptocurrency trading, hosting NFT marketplaces, or offering crypto wallets need to be transparent in their store listing about the financial nature of the product and, in applicable regions, meet the same licensing bar as other financial apps.
Commonly caused by an NFT or token-based game that doesn't clearly disclose the real-money value of in-app blockchain assets, or a wallet app launched without the additional financial-services disclosures Google requires.
"Your app facilitates cryptocurrency exchange or blockchain-based transactions without the required disclosures, per the Blockchain-based Content policy."