Art can be many things. In the case of most masks it is both sculpture and painting. When the artists of Europe in the 19th century first saw masks imported from West Africa, they were stunned. Gradually the style of modern art began to change on both sides of the Atlantic. I love the beauty of tribal masks and that is the first thing I look for.
Anthropology is equally important. Exactly in what culture was the mask used or meant to be used? Why, how, when and where was it made? Is it spiritual, ceremonial, entertaining, martial or for some other purpose? There is lots of background info you can learn.
This mask is a ngaady a mwaash from the Kuba people in the Congo for ceremonies in royal courts in 1890-1910, and is now in the Peabody Museum at Harvard University. It is authentic and very expensive. If you search the internet carefully you can find an equally beautiful, African-made reproduction for $200 or less. Don’t bother with thrift shops.