Why do we need such a cable?
You need it, wherever a conventional connector protrudes too far out of the socket.
In my case it was a TV decoder with a USB port for a hard drive that is in the closet and offered only 4 cm of space for connecting a USB connector on the side. This place was not enough to plug a standard USB plug, without kinking the cable.
The adapter fits, the connected drive is recognized and works without problems.