My two penneth worth.....
When I was casting I always wore a full clear face shield and it saved my sight when a mold let go once, a charge of molten silver hit the worktop, found a drop of water and blew all over the place. I had a 2mm ball melted into the shield right in front of my left eye, but I still have my left eye
I have to wear glasses anyway for close work so the face shield is good for me.
I would say that the foundry safety glasses make good sense for smithing, right kind of light radiation, what we need is a suppliers name if anyone can think of one