what is the importance of nebulae?

the most important aspect of nebulae, by far, is their star forming potential, they are the main star making powerhouses of the universe, and essential to the growth and creation of galaxies, (some nebula will very rarely become a galaxies) leftover star making material will also form into planets and other parts of a galaxie, since they make stars, you could also say that nebulae are essential to life in the universe   and to our own creation.