Why do icons appear with a jagged edge in Word but not in PowerPoint or Excel?

vIcons > Support Help
This is the way that all Microsoft Office applications render (display) imported vector picture files. After inserting the icon, an additional step is required to convert the vector file to something that Microsoft Office applications understand and that’s a Microsoft drawing object. This is done simply by ungrouping the inserted icon. In PowerPoint and Excel, the vicons add-in does this for you but Word doesn’t support that capability so you need to perform this extra step for each icon you insert.