The more information about a topic you have in your head, the more likely you are to see the connections between subfields, how various bits are important and unique or just ho-hum standard implementations.
I regularly see people in some niche area say "look we have found this amazing new way to handle the data-flood", only to tell them they have reinvented NoSQL or a message queue, or a technique for dealing with matrices that the image processing or simulation folks have been doing for years (and all of them poorly, making recognizable mistakes). A breadth-first overview has much advantage.