empty paper cups

Unfortunately the paper to-go cup acting in the first episode of the new season of Slow Horses is very bad. Why, why?!, can actors not act with an empty cup? Why, and I am genuinely asking, can we not put a little water in the paper cups so they have some weight to them, so the actors handle them not as a three-dimensional piece of paper but as a vessel for actual liquid that human beings drink? Why are we still, in the year of our lord 2025, when Andy Serkis can cover himself in dots and be turned into the most realistic monsters against which even bad actors convincingly act, are we still waving paper cups around like they are batons? If this is a liquid problem, could we not weight the cups with rocks? Could we not create a special cup insert that mimics the feeling of holding an actually filled cup? We must get our greatest minds working on this.