Background process is used in different applications to perform various activities in the background, which doesn’t require any kind of user interaction. Mainly CPU centric long running processes are designed using the background process. Background processes have a significant role in Windows 8 Store app development compared to other areas. The requirement for background process arises due to the new process life cycle introduced in Store apps.
Refer my article on Windows 8 – background processing to understand the importance of background process in Windows 8 store app development.