Their product is hand held test equipment, and they are too small for a customer cruising the trade show to see very well. So, they print a big picture of each meter, with a few words about what it does, and then put actual product on a shelf below the trade show graphic. The customer can then get a product demo on the spot.
I always tell people that the job of the trade show graphic is to create enough customer interest to bring them across the threshold of the booth. After that you do your sales job.