Speakers look sturdy but their business end, the paper or fabric cone and the delicate tweeter, dents and tears with the lightest poke. The heavy magnet inside also makes them front-heavy and awkward. Wrapping each speaker so nothing presses on the drivers is what keeps your sound quality intact through a move.
Pro tip: A square of stiff cardboard cut to the driver size makes a perfect protective buffer over the cone.
Watch out: Speaker cones and tweeters dent or tear from the lightest pressure. Never let anything press on the driver face.