Working from home is actually a win-win model. It reduces some costs of a company, makes a company ready for working in unusual situations. Besides, it lets employees work comfortably, spend no time for commuting, makes them intervene in work anytime.
Not necessarily, as they have to have offices anyway. Also, if the people at home are less productive or make less impact on customers, it is a cost.
Vice versa at my company. The employees have claimed it and their performance has increased, said by the board.