The practical applications for this thing are insane. On a larger scale, it can be used for damn near anything. Spiders, while creepy, are so mobile and getting their movements down and usable is a massive accomplishment. It can navigate steep inclines over rough ground, carry hiker or rock climbing gear. Haul injured civilians from hard to reach locations. Investigate foreign planets. This on Mars or the Moon, could navigate any terrain. Volcano environments with high sulfur in the air. All kinds of stuff.
I would love to get one big enough and mount guns to it for home protection. Giant robotic spiders with frickin' lasers.
If we're lucky, someone will combine it's power source with the bio-mass powered robots (read as flesh eating). That'd be great.