You don't need their cable. The head unit should come with a USB extender cable that your installer should plug into USB Port 2 in the back of the unit, and should place in a convenient location for you to reach. You can then plug any USB to Micro USB cable into that extender cable.
Now, you do have the option of having your installer also plug another extender cable into USB Port 1, so that you can conveniently access that port as well (for Apple Car Play or for an ipod or other USB storage device).
Either way, bottom line is you don't need to spend $30 on their cable. That cable is for the AppRadio feature (which is unnecessary if you have Android Auto).