Edgar Degas, who is one of my favourite artists, increasingly turned to using pastels instead of paint towards the end of his life and career. What led him to his new found preference?
It is for similar reasons that I find myself attracted to using them. For example, as a drawing medium it is possible to create an image, especially an impressionist image, very rapidly and without all the separate processes of sketching, refining the shapes, colouring . It can be all done in one process, if you like, so you are able to work quickly and spontaneously, something that would be hard to do while painting an oil painting for example.
Blending the colours, which can be done with a stump or your fingers is also a lot of fun and can create some great effects.
For example, another artist who loved this medium was Odilon Redon, who blended the pastels in a way that created a surreal, dreamlike environment, especially in his backgrounds.