Federal employees are left in the dark about what will happen if a budget is not passed or the debt limit isn't increased. They resort to reading the news clips, searching for answers online, talking to each other, etc., which is a terrible waste of work time. The rumor mill runs rampant, and the lost productivity has costs that no one has calculated.
Communicate exactly what will happen (who would be furloughed, who would not, who would lose their job). Instead of having everyone worried and wasting time, only those who may truly be affected would have lower productivity.