I have a Jet 1642 which uses a similar guard. I find it too distracting for finishing cuts, but I do use it for roughing blanks that are larger, off balance, or suspect in any way. I didn't use the guard at all when I first bought the lathe, but started using it after reading a couple of stories about very-experienced turners getting their faces smashed up in turning accidents. It's a small inconvenience for the protection it provides.
--Geoff