There's a practical concern there which is really relevant with little ones running around: glass breaks easily. A plastic bottle or cup or whatever vessel can

There's a practical concern there which is really relevant with little ones running around: glass breaks easily. A plastic bottle or cup or whatever vessel can fall from a shelf or counter to the floor and be unharmed and not harm any people. Glass containers, not so much. It's only viable for sensible humans with good coordination, and a lot of fully-grown ones don't even have that!