Those plugs are better than any silicone plugs.
It won’t take smell
It is more BDSM-ish
It is more beautiful and effective
Asides of being lightweight, it is also thick and of high quality because it doesn’t have the empty place inside. It’s a full glass.
So it won’t break unless you drop it like super hard or drive over it with a Tank or whatever.
Shortly, it is for the people who count the quality of the pleasure as the most important factor when getting something from a sex shop!