Processes save time and money by guiding experienced professionals through a series of time-proven best practices to reliably create something of value. By not following a process, you make things up along the way, reinventing the wheel for each project.
The primary advantage of a process is that it manages a number of common but potentially vexing problems and pitfalls early in the game. This saves time, money and frustration down the road and positions the project for success. Processes are all about success.