Today over at Derek's blog, he is writing about learning outside of your field. He talks about chemists learning biology etc... I had talked here awhile ago about "learning others languages" in a post that I can't find. My basic idea was that lawyers have their own vocabulary. Chemists have theirs, and biologists have theirs. Learning the "new" vocabulary lets you talk to those people more quickly. In order to learn their vocabulary, you have to learn what they do. It is totally invaluable. It leads to promotions. It leads everywhere upwards. I just recently got given more stuff. The reason I was given the group was because we need them to operate across some silo's we have. I speak both languages...so am one of the few who can break that wall down.
There are some people who just won't or can't do this. They have their little area of expertise and won't expand out. You need those folks, as frequently they are really good at what they do. However, they won't be moving up the chain.
The further up you get, the more different groups report in to you. The more "languages" you speak, the better/quicker you will understand what they are talking about (and when they are full of it). In addition, you more rapidly can solve the problems if you understand what is normal for an area, what they expect, how they think, and what they are trying to do.
SO... for those thinking it is just good for your science... it is also really good for your career.