Thankfully I’ve never seen this done. Although I used to regularly rake my co-workers over the coals for not wearing a face shield while wire-wheeling rims.
If you think wearing a grinding mask is uncomfortable, wait until you get shrapnel in your eye.
Came with my grinder (MasterCraft). It came with the half-open style you mentioned as well, and I use that one for my grinding wheels/flap disks.
The guard change mechanism is pretty slick too. Once you get the wheel off its a tool-less cam lock mechanism