With PCIe cards this makes more sense, although it would require the card to have an extra power connector (either SATA, molex or PCIe).
When the USB 3.1 port is on the rear panel of a motherboard, it makes it more difficult to apply the approach power planes, especially on cheaper motherboards, as well as drawing power directly from the 24-pin ATX and directing the appropriate power around the processor.
Nevertheless, motherboard manufacturers want to tackle this head on.
As far as we can tell there are a handful of IC manufactures that can provide controllers to be placed in products, but ASMedia are more ready than others to actually sell the components.
Without this, the system would not recognize the device or it would enter a speed mode indicative of PCIe 2.0 x1 data transfers eventually ending up in an IO error.
Also, our setup did not want to work in USB 2.0 mode at all.
This means that the device requires two USB ports in all, which is understandable for a dual m SATA device that requires power but perhaps somewhat limiting for devices with only one USB port.
There was a little coil whine during system writes, but as mentioned this device is still in development, and hopefully all these issues can be ironed out.
Both the card and the enclosure are still in development, and we had a difficult time to get it to work.
For example, with the Rampage V Extreme and the USB 3.1 card, the enclosure had to be plugged in at power up, with power and data both connected to the card.
The Type-A versions will support 900 m A charging at 5V, whereas Type-C will do 3A at 5V, suitable for 15W.
In order to get the 100W charging and implement the enhanced power standard, the power delivery delivery has to be built into the power module around the USB 3.1 controller.