I remember a long, long time ago, working on a project that handled lots of different types of physical quantities: distance, speed, temperature, pressure, area, volume, and so on. But they were all just passed around as "float" so you'd every so often run into bugs where a distance was passed where a speed was expected, and it would compile fine but have subtle or obvious runtime defects. Or the API required speed in km/h, but you passed it miles/h, with the same result. I always wanted to harden it up with distinct types so we could catch these problems during development rather than testing, but I was a junior guy and could never articulate it well and justify the engineering effort, and nobody wanted to go through the effort of explicitly converting to/from primitive types to operate on the numbers.