Games also use this because it's a straightforward way to almost guarantee a physical ordering of the files in the VFS, which is/was a common optimization strategy in the days of CDs and hard drives (profile what order the game needs files, then put them in the archive in exactly that order = tada, loading 4000 files behaves like a sequential read).

Another reason is that certain operating systems originating in the state of Washington have performance problems when you access small files or directories containing many files.