Comment by agarsev

Since an organism characteristics depend a lot on its evolutionary history, classifying organisms like that helps us make predictions and assumptions based on our knowledge of related organisms, so it's quite beneficial to humans. Also, the other classifications like tree, shrub, fruit, whatever, are also valid and used in biology, just not the main classification system. The other feature of phylogenetically classifying organisms is that it's valid for all life, which is a nice property.