In the nineteenth century why was it more necessary for art to provide accurate res presentations of life and objects

We are talking about Realism, as an art movement in the 19th century.  

In the 19th century. it was more necessary for art to provide an accurate representation of life and objects.

Realism supported the acute observation of objects, portraits, and life situations. Realism depicted nature and things in a modest and detailed way. In the 19th century, France had many Realism artists in literature and painting. Among the important artists of Realism, we find Gustave Courbet and Jean-Francoise Millet. They found more necessary for art to provide an accurate representation of life and objects.