If your work involves regular contact with speakers of foreign languages, being able to talk to them in their own languages will help you to communicate with them. It may also help you to make sales and to negotiate and secure contracts. Knowledge of foreign languages may also increase your chances of finding a new job, getting a promotion or a transfer overseas, or of going on foreign business trips.
Advancements in technology have made it possible for people from all over the globe to easily interact with each other with the press of a button. Because of this, corporations are making extensive efforts to establish global presences. As everyone moves toward a global society, it is becoming imperative that people speak more than one language in order to be able to communicate effectively with others from all over the world.
There are certainly benefits to being able to communicate in more than one language, in particular it can be phenomenal for the number of job opportunities a person has. That said, it is a little silly to require somebody to learn another language if they are content communicating in the one that they know, it's their choice if they want to expand their horizons or not.