Yes. Defense-in-depth. In China, most hospital red zones required 3 layers of PPE, whether that's two masks and a face shield or such. One layer alone is not very good, and a face shield alone is no good. A mask and a face shield are very good, especially for confined spaces like subways and busses where there are jerks coughing and sneezing all over without hygiene or manners.
According to the MIT paper, a typical sneeze will travel over 20 feet.
Additionally, there is mention of the velocity of the particles may be able to penetrate the mask, so a face-shield could help with that, too.