62 hours between and Hawaii and here, with no heat or air conditioning. No inboard navigation system, sleeping 20 minutes at a time while in constant contact with the ground. I can see all kinds of practical uses for this, so I think the “human endurance” test was an overrated part of this achievement.
Why would they need to sleep no more than 20 minutes?
That's the current problem with electric vehicles (so to speak). Once the vehicle itself is sufficiently efficient to perform, the energy to keep the occupants comfortable, exceeds the propulsion need.