They did completely overhaul the equation system in Office 2007 so that you edit them with unicode text instead of the proprietary OLE editor from previous versions. The document [1] describing how they use unicode characters to structure mathematical expressions is pretty interesting, even if you never touch MS Word again.
[1] https://www.unicode.org/notes/tn28/UTN28-PlainTextMath.pdf
Word also supports LaTeX for equations! https://support.office.com/en-us/article/linear-format-equat...
The thing is that time invested in learning superior alternatives is already spent, and there's no point taking the risks just to try for no reason.
Just like I will not create another website in FrontPage.