AutoCAD (and other older platforms) started out as more of a drafting tool, allowing for the transition between paper and electronic formats. Design intelligence wasn't a big part of the tool at that time.
Revit was engineered to be more of a design tool, with engineering data being an important part of its application.
Although AutoCAD is not completely obsolete, going forward Revit is hands down the more sophisticated tool and without question the more valuable certificate to have.