Aside from fantastic hair and piercing eyes?
They can both help diagnose dementia.
Recognizing famous pop culture figures can be used as a measure of several mental tasks, like the ability to recognize faces (which can be a really complicated process, resulting in the common phenomenon of seeing faces in random objects called pareidolia) and how easily a person can name things. One problem that the researchers came across when evaluating people was how old the original face test was. A person in their 70s or 60s may know what Emperor Hirohito looked like, but could you expect that of a 40-year-old coming in to see if they had early-onset dementia? So the team at Northwestern decided to modernize the sample. Einstein made the cut to stay, since his mug can still be found everywhere in our culture. But now we have Oprah instead of Martha Mitchell (the wife of Nixon’s attorney general, evidently).