When a Solidity function is compiled into EVM bytecode, a 4-byte function signature is generated to identify the function. The smaller the function signature, the less gas it costs to look up. I've deployed a smart contract on Sepolia to provide a basic demonstration of this effect.
0xb62a1D4eF19E8c25B025B7831EF39d39E7Fb9E1Aeth_estimateGas results: