I don't understand. I use lots of hobby stuff with USB ports. I have to lookup the vendor ID to make it read write in linux by default. Presumably getting a proper ID makes this pain point go away from consumers somehow? What's the gain I don't understand it?
Using your own VID/PID allows you to write and distribute a driver that can be tied to your gadget rather than using a generic driver. Widely distributing products (even if they are "hobby stuff") that re-use the microcontroller's default VID/PID is also usually against the license agreement with the chip vendor and can lead to problems down the road.