The maximum file size of a file system determines how big of a file can be created. Most “normal” files are relatively small, and can be handled by practically all file systems. However, certain files can be quite big, such as backup archive files. If a single archive file is too big for a file system, then the archive must be divided into smaller portions, which is troublesome.
Another application where large files are needed is virtual computing. The disk of a virtual machine is often a single file from the perspective of the host operating system. For example, in order to create a virtual machine with a 200GB hard disk, the host operating system needs to handle a file of up to 200GB size.