A better example would be seconds to minutes. I think i recall a jwt related cve related to timestamps being misinterpreted between sec/ms for example.
Adding seconds to minutes can actually make sense. A minute plus 30 seconds is 90 seconds, or 1.5 minutes. Whether your type system allows this, though, is up to the project.
You can't add seconds to kilometers, or to temperature, or to how blue something is.
