Biggest safety concern regarding face cages are mallet swings into the face. They can injure your eye (priceless), teeth (in most places expensive), or break your jaw or cheekbone (painful). Negative impact of a face cage on a crash seems a very unlikely, rare, and particular scenario.
High sticking is banned. Slashing is banned. Still you get a blind backhand or wild follow though from time to time, often just by purely bad judgment of the player who does it, rather than evil intent. It happens, and I would personally not accept the risk of such injury on myself, which is why a play with a facecage. I am personally not worried about landing straight with the face cage on the ground. At least, I would be much much less worried than instead accepting the risk of being hammered by a mallet in my face.
The argument that they are not designed or even counterproductive during crashes is hard to judge to me. Honestly, when it comesto why we wear a helmet I see more benefits in wearing a helmet in avoiding concussions or bad injury from mallet impact, rather than bike crashes. Of course bike crashes are much bigger potential danger in the worst case scenario, but mallet impact is more frequent and a huge potential danger by itself. In most crashes you choose the speed at which you go, you have some possibility to react, you often do not land head first etc. while in EVERY scenario where you get hit with a mallet on your head you have no control, no defense, no reaction. You can have big wounds, broken skull, concussion and even die and you didn’t even see it coming. A mallet is nothing else than a bludgeoning weapon. Being hit in the face will likely not kill you is perhaps the only argument why face cages are secondary to a helmet when it comes to hard mallet impact.
So to me the protection against bike crashes is secondary to the protection against mallet impact when it comes to helmets. But I am not arguing against wearing helmets that do protect well against a direct impact of your skull on the hard floor, such as cycling helmets. Of course this is essential too, because it can be fatal in the worst case. Face cages to me are a huge safety boost when it comes to things you have no control over, like your opponent’s wild swings.
Recently I got a huge bruise from a swing on my upper arm. A clear and painful foul that was not even called. One that would have severely injured the face of a shorter player without a face cage. I honestly think we may have to get stricter on calling swings, even if no impact to no body part happens.
OK, I leave it here, lots of points to discuss.