It makes sense, yes even mandatory. But Tiny, material + production costs probably well below 99 cents.

Did the thing precisely and get unpacked. First thought: BOAH is a tiny piece of rubber!
In the box of RX100III would yoy. the place where battery and wrist strap are in it had space for about 4-6 pieces of it. (Or 2 pieces + 2 extra batteries ...) It seems almost as if Sony earning on the camera and nothing needs to bring in the money through those parts. ... No, it can not be sure, but it works just as, if not accompanied by such a standard in the design of the actual camera "forgotten" hardware bug fixes in this price range.

But perhaps it is also fully intended that one or the other camera out of his hand slips, on the need to buy a new ...

Otherwise I can not explain how such a tiny and certainly extremely inexpensive piece of rubber is not supplied as standard to me anyway.

Unlike I suspected would summarizes the rubber part the camera is not completely one, but is adhered only at the front and even goes over the front rounding. (About 5 mm towards the camera back)

After all, one can hope that Sony will certainly have ensured that keeps the adhesive material a) reliable and durable, b) not to paint the camera dissolves, if you want to remove it once, c) is left no catastrophic Klebereste during removal.
At the very least I would expect that. In a 0815-third, I would certainly be much more skeptical.
That must a then probably ever be worth 18 (15 + 3 shipping).