It can bring many benefits to the employers. The most important is they can retain staff who would otherwise leave. When an employee leaves, they take all their knowledge and experience with them, and that has to be replaced at the employers cost.
In terms of just money, if there is a telecommuting workforce, then there is less desks, therefore less floor area to rent or buy, not forgetting other facilities such as toilets and eating areas, lighting, and aircondioning, all saving the employer money.
Not all jobs can be done by telecommuting, but primarily knowledge based jobs can easily be done if the correct tools for communication are provided.
Telecommuting can be a win-win solution for the employee and the employer.