Because they’re rad, man. Personal mobility is on the upswing, as more folks work from home and commute less. Shopping online diminishes the need for motor transportation even more.
The upshot is that a lot of us can occupy smaller orbits most of the time (especially city-dwellers). In many locations, it’s totally reasonable to e-skateboard to the park, around the neighborhood, or to the convenience store.
People who commute into a city and then walk to work can also use a good electric skateboard.