Hot take, but a character that demands zero-space between the letters at the end and the beginning of 2 words - that ISN'T a hyphenated compound - is NOT nice typography. I don't care how prevalent it is, or once was.

I don't know if my language grammar rules (Italian) are different than English, but I've always seen spaces before and after em-dashes. I don't like the em-dash being stuck to two unrelated words.

That sounds like a strongly held opinion rather than a fact.

I like em-dashes and will continue to use them.

agree. it implies a strong relationship between the two words it is inserted between - not the sentences.