I do. I think it makes a huge difference
The top one, while far from prototypical, is a good example (coal for the Giants, plastic for Rudolph). Appropriate, as aside from Odell Beckham Jr, all Giant fans got was coal. The bottom one, at least shows a "better" coal car. On the Giant car, I stuffed it with foam and glued it down. It wasn't difficult, but on the other car I just turned the plastic coal load upside down, stuffed a little bit of black packaging foam in it and covered it with a layer of coal. The foam was to minimize coal use, avoid some weight and some cleanup, if someone, or the dog, kicked the car.
Also, for glue, I used diluted Elmers, but it really dulled the coal. I like the shine of the "clean" coal.