My quick understanding from the video and stuff, and I'm not an expert, is that they send a pulse of juice followed by some data. The USP is that it's safe power and turns off withing 3ms, which is short enough to not kill you if you touch it. Hence why the power pulse is 1.1ms wide.
So, the supply sends a 1.1ms pulse of HV power, some data bits, then waits for the far end to say, "OK, send me more". But this is also supposed to work over thousands of feet and there's a round trip time involved which goes up as the wire goes long. At first I thought this would be a killer since it would slow down the pulses, but I am stuck in data comms mode. Does it really matter if the pulses are taking longer to generate? On the face of it, all that would do is reduce the throughput of power (it would look like PWM, although it isn't really). As the cable gets longer your power capability reduces. Just like resistance, kind of. Actually, 'in addition to resistance'.
There would need to be some clever smoothing out of these power pulses, but it's surely doable. On the face of it, calling it digital electricity wouldn't be far off the mark. To anyone with a scope it would look like that and they are effectively packetising the power. Could well be one to keep an eye on.