Why do you need ETH to swap ERC20?

Why is ETH necessary for swapping ERC20 tokens? This question may arise for those new to the cryptocurrency world, particularly those exploring the Ethereum blockchain and its ERC20 token standard. ERC20 tokens are built upon the Ethereum network, utilizing its smart contract functionality. ETH, the native currency of Ethereum, plays a crucial role in these transactions. It's like the fuel that powers the network, enabling the execution of smart contracts and, consequently, the swapping of ERC20 tokens. Without ETH, the transactions would lack the necessary means to be processed and completed on the blockchain. So, when you want to swap ERC20 tokens, you need ETH to ensure the smooth and secure execution of the transaction.