I would hope this is not the case. If it was, I don't see how it can be legitimately called a hardware proof-of-concept. I agree, though, that the lack of outside power and ground doesn't seem to be explicitly stated in the writeup. The video comes a little closer, with one of the questions after the talk asking whether using more pins would make things easier: (from the automatic transcript of https://youtu.be/C7H3V7tkxeA?t=1868, punctuation added and some typos corrected):

"But do you see a way to actually get more power into your setup, maybe using other power sources other than the two pins?"

"So the question is about would there be some way to do more arbitrary changes through redesigning the implant? One of the goals was to fit with only those two pins so that a single piece on the motherboard could be replaced. You know, with a dual probe soldering iron you can pop it out and stick a new one down in a matter of seconds. So yes, if you have more pins where you can get more power from you can do much more interesting things, but that would require a different set of changes to the motherboard."

I'm pretty sure the author is claiming that their FPGA implant was working off of just two pins on the motherboard. If they are relying on some technicality (such as "all the other pins are from a source other than the motherboard") this would make me write off the entire article as untrustworthy. But until there is proof to the contrary, I'm inclined to believe that they used no outside power or ground, and that they indeed built a hardware POC.

Edit: I sent email to the author asking for clarification.