Before revision:  In many studies, the goal is not only to describe a network, but to investigate how this network is changing under different conditions, with respect to certain diseases, or between different species. While methods for comparing two networks exist, this is not the case for comparing multiple networks, although this is a common aim of many studies.
After revision:  In many studies, the goal is investigating complex-phenotypes under varying conditions, it comes naturally to employ comparative network methods. While approaches for comparing two networks exist, this is not the case for comparing multiple networks, although this is a common aim of many studies.