Going back to the Windows 95/98 era and Windows 2k at work I remember a link or line of text in one of the Equation Editor dialogs where they said you could upgrade to the full MathType.
It is the compatibility with old documents that could be an issue with Microsoft's complete removal of the old Equation Editor. I suppose anyone dealing with legacy documents should be using a vm with Win2000 and Office 2000 really.
> It is the compatibility with old documents that could be an issue with Microsoft's complete removal of the old Equation Editor
https://support.microsoft.com/en-us/office/equation-editor-6...:
“Equation Editor 3.0 objects will still display normally if you have MT Extra font installed (if you don't have the font, you can download it)”
I think the equation is an OLE object with a preview image.