It's pretty well known here on the forum,but not extremely widespread around the entire hamster community as far as I'm aware.Any sort of mineral or vitamin or salt etc stone wouldn't be safe as that page would state,not only for intestine and kidney related problems but because it would also affect the overall health(dietary imbalances etc which could end up leading to a generally unhealthy hamster)and in the case of salt it would cause dehydration.Excess salt is no good for any creature
I know it can be very confusing,especially since there are some people with the opinion that if a hamster isn't chewing on them excessively they're fine(not really true though,as even a tiny bit over what is necessary in any particular vitamin or mineral etc can cause very serious health problems).