This is way cool, but the company has a few challenges to face to be "serious, eco-friendly transportation devices that could replace your bike, scooter, or maybe even your car."
I live and work in manhattan and for the summer I've been skating to and from work nearly every day (40ish blocks). According to my research, skateboards are considered "play" devices. Whereas bikes and all motorized vehicles are required to be in the street, skateboarders under 14 must wear a helmet and are not allowed to ride in the street. Older skateboarders have the option, but not the requirement to ride in the street. With the narrow streets, stop and go traffic, out of control cabbies, and people not used to looking for skateboarders, I feel much safer on the sidewalk.
There is a law that prevents the reckless operation of skateboards on sidewalks (http://codes.lp.findlaw.com/nycode/ADC/19/1/3/19-176.1), and I always take care to be courteous and provide plenty of space to all pedestrians.
Where there are bike lanes available, I'll take them, as that also seems to be a legal option, but I've had more run ins with pedestrians in bike lanes than on the sidewalk.
I've been stopped by cops twice and told I could not ride on the sidewalk, yelled at by private security and pedestrians, and had pedestrians step out in front of me without looking when I had complete right of way in the bike lane--causing me to have to bail.
This said, for any company looking to use skateboards to revolutionize urban travel, education campaigns at all levels will be necessary.