It will boot the front USB port. The only main use for this generally is the USB Recovery image, which is a special kernel/initrd/firmware image that restores the internal boot flash if that were to be corrupted.
There is a VGA header on the motherboard, I'm not going into details on that, though I believe there are forum posts on it. I know people have booted other OSes on the hardware, as it is x86, so Ubuntu/Windows/etc would run on it. But without VGA hacking, using those is not very ideal.
Doing this would allow general usage of the hardware. Trying to continue using RAIDiator on the system with your own kernel/initrd is not trivial, and will not be explained further.