With one coworker I believe its perfect, because any of the two can end the conversation.
When its 6, though, you get caught up in conversation from the other folks, just when you're trying to get into flow.
There's a happy median.
Don't throw darts at employees who don't engage in dart throwing. Don't be excessively loud. Don't drum on other people's desks.
On the flipside: don't get angry when people aren't enforcing library rules around you. Use headphones as a signal that you don't wish to be disturbed (and to block out noise, obviously.)
Et cetera.
The offices in which I've gotten the most work done had a low to midlevel din of casual conversations and banter, like a place that lets humans be the social animals they are, while still encouraging some kind of collective respect for the idea of getting work done. It's a hard balance to adhere to consistently, but I'd rather struggle with the vacillation than work in a library.
In fact, this is the very reason I gave up working at home after two years: it's too quiet. You can hear a pin drop. A library to me has the ambiance of a funeral home, and encourages similarly dark thoughts. Needless to say, I got a lot more done in an office with an officemate, where we were both banging away at our keyboards and casually chit-chatting all day.