Regency era women of the ton wore beads (glass, not plastic) all the time . . . but on their dresses and reticules and even shoes! There’s a lovely example of a Regency beaded gown here. Just imagine how much time it took to sew all those colored beads on, not to mention drawing out the design in the first place. Years ago, I made my own wedding dress and sewed tiny pearls on just portions of it, and it took hours of work for my simple decoration. This is far more complex. So I would imagine only the rich could afford such a gown.