What is so special about humans manipulating measuring equipment versus robots? This notion that we must send people into space is just romantic.
The romanticism of the adventure is one of the strongest motivators of exploration. Take that away, and it's just work.
Besides, there are practical reasons for sending humans into space. One day, in order for the human species to survive, we will have to move off this rock and travel to other regions of our galaxy. We might as well start our baby steps now.