I am not an expert on the relative merits of oars and man powered paddlewheels.
But it is a historic fact that man powered paddlewheel boats and ships were used in China for centuries, so it may be presumed that they had some advantages over oars for some purposes.
The first mention of a paddle-wheel ship from China is in the History of the Southern Dynasties, compiled in the 7th century but describing the naval ships of the Liu Song Dynasty (420–479) used by admiral Wang Zhen'e in his campaign against the Qiang in 418 AD. The ancient Chinese mathematician and astronomer Zu Chongzhi (429–500) had a paddle-wheel ship built on the Xinting River (south of Nanjing) known as the "thousand league boat". When campaigning against Hou Jing in 552, the Liang Dynasty (502–557) admiral Xu Shipu employed paddle-wheel boats called "water-wheel boats". At the siege of Liyang in 573, the admiral Huang Faqiu employed foot-treadle powered paddle-wheel boats. A successful paddle-wheel warship design was made in China by Prince Li Gao in 784 AD, during an imperial examination of the provinces by the Tang Dynasty (618–907) emperor. The Chinese Song Dynasty (960–1279) issued the construction of many paddle-wheel ships for its standing navy, and according to the British biochemist, historian, and sinologist Joseph Needham:
"...between 1132 and 1183 (AD) a great number of treadmill-operated paddle-wheel craft, large and small, were built, including sternwheelers and ships with as many as 11 paddle-wheels a side,".
The standard Chinese term "wheel ship" was used by the Song period, whereas a litany of colorful terms were used to describe it beforehand. In the 12th century, the Song government used paddle-wheel ships en masse to defeat opposing armies of pirates armed with their own paddle-wheel ships. At the Battle of Caishi in 1161, paddle-wheelers were also used with great success against the Jin Dynasty (1115–1234) navy. The Chinese used the paddle-wheel ship even during the First Opium War (1839–1842) and for transport around the Pearl River during the early 20th century.
So a study of the history of man powered paddlewheel vessels in China to see what their uses were and how they compared to oar powered vessels would be useful.
Of course your undead zombie crew would not get tired or need food and water like living crew members. And that should change the relative benefits of using oars or paddlewheels in ways I can't think of at the moment.