Decentralized Finance (DeFi) revolutionizes traditional financial systems by offering a permissionless, censorship-resistant infrastructure that enables developers to focus on their core business logic using composability. This unique feature allows DeFi applications to interconnect, creating innovative financial products and use cases beyond the scope of traditional systems, which are often constrained by high entry barriers and legal costs. DeFi's transparency, enabled by open-source, immutable ledgers, contrasts with the opacity of conventional financial services, which can lead to systemic risks, as evidenced by the 2008 financial crisis. While traditional finance requires regulatory compliance, which can be costly and restrictive, DeFi proposes a modular compliance approach that integrates compliance tools without stifling innovation. The composable nature of DeFi, described as "Money LEGOs," allows for the creation of new applications by combining existing protocols, fostering rapid innovation and network effects. However, this interconnectedness also introduces risks, such as potential vulnerabilities in smart contracts and increased attack surfaces. Despite these challenges, DeFi's open-source, permissionless framework offers a competitive and innovative environment, promising a bright future for modular financial systems.