But it's not even strictly correct from a technical point of view. In Unicode, Hangul syllables can either be encoded directly as a single codepoint, or composed from multiple codepoints each representing a single jamo.

One could conceivably devise a Morse code encoding that simply uses the Unicode codepoints of the syllables. It would be a bad way to do it, but it's an option. Composition isn't a hard requirement for Hangul encodings.