Return by value vs return parameters

TestReturnPatterns.sol

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
contract TestReturnPatterns {

    struct Big
    {
        uint256[256] data;
    }

    function returnByValue() internal pure returns (Big memory big)
    {
        for (uint256 i = 0; i < 256; ++i)
        {
            big.data[i] = i;
        }
    }

    function returnParameter(Big memory big) internal pure {
        for (uint256 i = 0; i < 256; ++i)
        {
            big.data[i] = i;
        }
    }

    function testReturnByValue() public pure returns (uint256)
    {
        Big memory big;
        big.data[0] = 0;
        big = returnByValue();
        return big.data[255];
    }

    function testReturnParameter() public pure returns (uint256)
    {
        Big memory big;
        big.data[0] = 0;
        returnParameter(big);
        return big.data[255];
    }
}