WinUSB is an application to assist in the process of burning any Windows 7, 8, 10 ISO or DVD to your USB drive and makes it bootable. This can usually be accomplished without formatting.
It is designed to do this for you in 3 easy steps, so it's not confusing or difficult. Simply choose a USB pen drive, select the necessary Windows distros (ISO and DVD supported), then define the new file system of the USB drive if you would like to format first. That's it.
This can be helpful when you do not need to transfer all of these files to your hard drive. You also have the ability to choose any number of Windows distributions for creating your own multi-boot flash drive. After burning is completed, you can add more distros to your flash drive by repeating the process.