People say that Markdown is isomorphic to HTML but HTML has <b>, <i>, <em>, and <strong>, while Markdown bold and italic almost always get transformed into <em>

People say that Markdown is isomorphic to HTML but HTML has <b>, <i>, <em>, and <strong>, while Markdown bold and italic almost always get transformed into <em> and <strong>, right? According to MDN the HTML standard defines clearly very different semantics for the elements, although IIRC there was once a drive to move away from <b> and <i> as presentational, which is why people started using <em> and <strong> instead but in a way as if they were presentational, kinda defeating the point. IDK, what do you think? "<b>: The Bring Attention To element" "<i>: The Idiomatic Text element" "<em>: The Emphasis element" "<strong>: The Strong Importance element"