Until about 2 (?) years ago, these glitters were sold everywhere in cake shops and food sections of the craft shops in the UK and you would regularly see them sprinkled on cupcakes etc. Then the issue came up in a national TV show (a contestant used glitter dust and the judge asked if it was edible) and all of a sudden, all shelves were emptied. The pots said 'non-toxic' on them and so people assumed it was safe to eat...apparently not the case. Back then, I was just baking for myself and family and I have to say, I used them (and ate it) and I'm still here ;-) but certainly wouldn't do so now. I have used them for cakes since (to make numbers on birthday cakes sparkle for example) but specify on the order form that these items should be removed before eating.
Here is a link to an article about "GlitterGate": "Storm in a cupcake: How Miranda star sparked pandemonium after question over 'edible glitter' she used on Great British Bake Off reveals it's 'not to be consumed"
Excerpt: "For years, cake glitter has been sold in pots labelled either ‘edible’ or ‘non-toxic’.Edible glitter is made from starch-based food products that can be digested by the body. Non-toxic glitter is manufactured from plastic and is not digestible."
Excerpt: "....prompted so much panic among viewers that ‘edible glitter’ has now been registered as one of the top ten food concerns in Britain by the Food Standards Agency."