Why does it have the words DON'T EAT printed on every single package? you don't usually come across such warnings on other products.
Your body likes having water inside of it, and doesn't like having glass shards inside of it
With millions and millions of those things around I’d guess quite a few get ingested accidentally and we don’t hear of them causing problems. It must be pretty safe (well as safe as eating a small amount of sand is).