What is the purpose of the outfits the demonstrators are wearing?
It kept them from being nude. That would distract from the product.
Haven't got a clue. Maybe they are just to blend in with the vehicles, or maybe they serve to protect the occupant of the vehicles. Or...maybe they're just fun and add to the sci-fi quality of the demo.
So that we'll assume they look like idiots because of how they're dressed, not what they're riding in.