I think it is just a difference in planning and preparation. For some people it is easier to do everything themselves. For me too, by the way. Now there is tons of info online about tickets, hotels, places and travelers insurance, so you can arrange, book and pay for everything yourself. And for some people, for example, my parents, it is much easier to go to a travel agency so everything is prepared for them. They do not have time to deal with it themselves.