The main reason is for networking. And working with friends, people you like and whose work you admire; also benefit from senior colleagues. Conferences are good and efficient way to get to know other researchers through their work and also personally. Another reason to go is to get a quick overview on recent knowledge and discussions on certain topics, sometimes loosely connected to area of your expertise. It is a fast way of getting wider perspective and to know about some issues you rarely read about.
The main reason is for networking. And working with friends, people you like and whose work you admire; also benefit from senior colleagues. Conferences are good and efficient way to get to know other researchers through their work and also personally. Another reason to go is to get a quick overview on recent knowledge and discussions on certain topics, sometimes loosely connected to area of your expertise. It is a fast way of getting wider perspective and to know about some issues you rarely read about.