I assume with the glass gems that you would not put them directly in with the food? Like you would vacuum seal them in a second outer bag? I wouldn't want those to come in contact with my food. Who knows if they would crack or flake, and if they are made in China, there could be lead in them. I doubt if they are food safe.
I like the sous vide weights you bought on Amazon better. The stainless coated in silicone seems safer. And you are not dealing with all of the pieces.