Art needs to be viewed in context. You can see this in the Impressionists on Paper: Degas to Toulouse-Lautrec exhibition, currently on at the Royal Academy in London. The interesting thing about this exhibition is that the works on display may never again be seen together due to their fragility.
A group of artists from the late 19th Century played with materials newly available due to industrial innovation and mass production.
Bright new alkaline dyes for paint and paper, oil and chalk pastels, charcoal in boxed sets, oil paint & watercolours in tubes, everything became so much more convenient and portable. You could now work away from the studio and en plein air more easily.
Degas often used different techniques and materials in the same piece, experimenting to see what could be achieved.
The Dancer Yawning from 1873 is the most striking colour example on show of newly available coloured paper.
Drawing shows the thought process. See how the right arm and left foot were amended in this large piece, Woman Combing Her Hair. Degas used charcoal and coloured chalk on tracing paper laid on board.
The status of drawing increased during this period, becoming more than just preparation for painting. They are signed, proof of finished works in their own right.