It’s more that they used to be shipped 2x4 unfinished, and would be planed smooth on site. Once the equipment and distribution was able to do the planing before it got to the customer, they had so much established practice that the installed timber would be smaller, they had to keep to what people were used to.






The character was created specifically because when we write we use different length dashes to mean different things—subtraction through to a pause for thinking.
The automated test will have no difficulty telling them apart. Are you saying it’s hard looking at the results of this tests? You might need to use a font that makes that easy (I agree many monospaced fonts don’t, but that’s not the character’s fault. Or include a step that replaces en with 2 hyphens and em with 3.