If you want it so badly, take a look at this script: https://github.com/SebLague/Digital-Logic-Sim/blob/main/Assets/Scripts/Graphics/...
If you replace all calls to DrawWireStraight with DrawWireCurved, you can make a custom build with rounded wires. It currently has some issues concerning anti-aliasing, and multi-bit wires, which is why it's not currently included as a built-in option.