The shell is certainly too soft and too thin to protect them from serious shocks, but against light already. It is thus a very effective protection during transport, as long as the danger exists only in colliding of bag contents. The sheath helps especially against visual impairments the surface by scratches. Because the plate is almost not heated, they can also go far in use keep in your pocket.
The cable bag is certainly very convenient. And when they were inside it is located in the event of shocks to selectively higher loads through the tough USB connector. Since it has only 3/4 of the envelope height you should insert the plug into the bag down. Look namely up out of the bag, so scratches during transport quite likely.
