Oh I agree it's still a silly idea with little real-world practicality.
I can think of a way it MIGHT be used, at least with an electric fork truck. Not as a constant power source, but for charging. Electric for trucks are typically parked in a fixed location where the charging station is - so you have machine standing still for some time with, very likely, the back side (non-screen) of the electronic device pointed right at a wall. And only a meter or less from said wall. About best case for uBeam. But yes, still way too complex when all you need to do is power the device from the fork truck's massive battery pack, the additional draw of that device running (which still needs RF wireless networkng!) would maybe mean you can drive the fork truck a few centimeters less per charge - meaningless. And no fancy pants ultrasonic transmitter and receiver needed.
It's sort of like the newest craze (so it seems) in model railroads - Dead Rail, which is a battery on board the locomotive and no power to the tracks. This is barely practical with current battery chemistry in HO scale. Smaller scales, forget it. In larger scales, especially G scale outdoors in the garden, it's been done for years - because if you think keeping track clean indoors is tough, try it with track left out in the weather, year around. An intermediate idea would be to power most of the track, and have the battery charge whenever there was sufficient power, but the battery would run things over dirty or deliberately left dead areas, thus extending the run time. This may be the sort of thing uBeam is trying to promote, since anything that freely moves around is never going to stay in line of site for full power transfer of one of their transmitters, but use it for opportunistic charging - maybe, just MAYBE it could do something. But since you can't set your portable device down, you can't hold it with your hand over the back, and all the other restrictions with ultrasonic transfer - in the end, nope. Not worth it.