Outsourcing has two beneficial side effects.

Welcome relief. Outsourcing a project can give your staff a break. If your staff has been working on one rush project after another, they might welcome the opportunity to get out of the kitchen and let someone else feel the heat for a while. Outsourcing can provide a welcome change in routine, and your developers can benefit from exposure to another software-development organization.

Reduced manpower fluctuations. Outsourcing eliminates the need to staff up for a rush project.