This one is just ahead of the solar-powered flashlight on the practicality scale.
No, the solar-powered flashlight is a thoroughly practical, useful tool available on the free and open market from a wide variety of competing manufacturers and vendors.
This aircraft is an interesting experiment showing the possible viability of a light, long-duration, high altitude aircraft requiring no aerial refueling. While this experimental aircraft is manned, the concept would likely be most useful in a UAV.