Even in a metric monoculture, mixing code with different system of units poses a problem. Worse, mixing code with no system and just a convention for what unit

Even in a metric monoculture, mixing code with different system of units poses a problem. Worse, mixing code with no system and just a convention for what units numbers are assumed to be in. Joining two simulation packages, on with length in mm and the other in cm provides a bounty of potential bugs. Sometimes this variation is happenstance but sometimes it can be important for precision. nm and ns are the relevant scales for particle physics while parsecs and seconds for astro and yet astro-particle physics is a thing.