I don't know if this is still the case or not but equations in Word can be upgraded to MathType. IIRC the Word equations were a basic version of MathType (i.e. developed by the same people). MathType included latex syntax and much better layout and formatting. It was the only way to stay sane when working on journal articles with collaborators who gave less than zero interest in latex (i.e. physicians).
The equation editor in Word straight up supports LaTeX now days. It also supports UnicodeMath, which is an actual standard and a pretty cool one at that. Sadly it has almost no adoption outside of Word.