Okay, i should dial it back a bit. What they're promising is cool. Low infrastructure, high pay-load travel is indeed interesting.

But they too are depleting a natural resource, just as petrochemical fuel usage does. And while we can find other storage mechanisms for portable energy (batteries, flywheels, hydrogen, what-have-you), there literally is no substitute for Helium cooling, by virtue of the laws of physics as we know them.

This is not worth giving up cryogenics.