First of all, it is fun and satisfying!
Alright, not everyone is a geek. Designing and making a PCB is also very practical and useful. PCB makes it possible to create reliable and small electronic gadgets for a wide variety of applications. A custom PCB means even more specialized applications. For example, if you want to automate a remote-control car, being able to custom design and make a PCB means it can probably fit in the case, and have just the right components to perform the task.
While some believe PCB design is not academic or a task for engineers, there are many employers who disagree. A well-rounded electrical engineer or even software engineer who can design a PCB is usually valued by an employer.