The main difference between Cash App and Zengo is that Zengo is a non-custodial cryptocurrency wallet that enables you to be in complete control over your digital assets as you hold the private keys to your funds. In contrast, Cash App acts as a custodial service that controls these keys for you and technically has ownership over your digital assets once stored there. In addition, Cash App offers its users only the ability to hold Bitcoin, with no other cryptocurrencies available. Another key difference is that Zengo is a fully Web3-ready app and DeFi gateway, while Cash App is a traditional standalone finance app.