There are times which that is convenient to use USB disks formatted with the old FAT file system, i.e. in office environment with mixed operating system.
In my situation we have a linux server (using ext3 file system), with several SMB shared folder used by all the MAC/Linux/Windows workstation: a very cheap backup system consist in a USB disk connected directly to the server, and a daily backup process that copy all the files from shared folders to this disk. In emergency this disk become the only way to get all files.
From here the most convenient way to use commonly a USB disk is to format it using the old FAT file system !