The unification of minus, hyphen, en-dash and em-dash is entirely natural. Back when I was in school ~25 years ago, in newly-non-communist Romania where ASCII was at best a distant idea, no one taught any difference between these signs. We did have different names for the minus sign and the dash used in writing (and Romanian uses a lot of dashes), but that's it.
We were taught to use the exact same sign for compound words, for other Romanian orthography, for separating words at the end of a line, and as one option for introducing parenthetical clauses - like this. And it was the same sign we used for minus in math class. A slightly longer dash was often used for one particular purpose*, though even that was not explicitly stated, and you wouldn't get lower marks even in calligraphy classes for using shorter dashes instead.
* Romanian uses these longer dashes when representing lines of dialogue, especially in literature, as in:
We were taught to use the exact same sign for compound words, for other Romanian orthography, for separating words at the end of a line, and as one option for introducing parenthetical clauses - like this. And it was the same sign we used for minus in math class. A slightly longer dash was often used for one particular purpose*, though even that was not explicitly stated, and you wouldn't get lower marks even in calligraphy classes for using shorter dashes instead.
* Romanian uses these longer dashes when representing lines of dialogue, especially in literature, as in:
-- I would like to go to the mall.
-- That sounds wonderful!