Why do we spend so much time on creating taxonomies?
Biology is about observation and learning from nature. If you categorize the species, it helps you in quickly understand what the species is about, what are some of its common characteristics, phylogenetics, etc. It has applications not just in understanding evolution, but in population studies, ecology. Why do we give humans names? So we can find them quickly and easily and associate them with certain characteristics. It is the basic human nature of using patterns to quickly identify objects.