I honestly don't know what the problem is for gaming, unless you're worried about breaking some on-field glass or optics.
From what we've heard so far, they're goggle safe. That's not saying that no further testing should be done, but we shouldn't rule them out so quickly.
If they won't break, they might also be a safer option for fields who use mesh screen goggles, as those leave the eyes vulnerable to shattered plastic BBs.
RS Type 56-1 & RS Type 97B & KWA M11A1 w/steel kit
KJ M1911A1 & KSC G19 + AI Grenade