Why does a Basler ace USB 3 camera not work on a USB 2.0 port?
The reasons for that a more physical than product related for the ace camera. All USB 3.0 (=USB 3.1 Gen1) camera vendors do have the same issues: At first a USB 2.0 port is only specified for 500mA of current. A USB 3.0 port does offer 900mA. Depending on the sensor the camera must be supported with far more than 500mA. So there is not enough power over one cable. Another topic is that the performance of USB 2.0 is massively different to USB3 Vision. The protocol itself is less stable, the CPU load far higher and the real-time capability worse. Altogether you would limit an ace camera with a connection to an USB 2.0 port.
As an alternative we have the dart and pulse cameras which use less power and support a USB 2.0 connection. But you still have to use a USB 3.0 (USB 3.1 Gen1) cable.