Actually, it plays quite a rather large role considering most of the problem we are having is squeamish governments and constituents unhappy with their fathers/brothers/sons/uncles/etc. going off to distant third world countries to fight and die, and most of those poor souls get offed patrolling dangerous areas for bad guys.
The entire purpose of autonomous vehicles (which is why it's funded by DARPA) is to remove people from hazardous situations. Ground vehicles are no different than UCAVs. Put a gun, a self-destruct charge, and a Millimeter radar or acoustic sensor on it and speed it up a bit and send it into bad neighbors. They try and screw with it up close and it blows up and kills them. They shoot at it, it can shoot back and informs the infantry where the assailants are. The less times Johnny Walker gets shot doing mindless and repetitive sweeps of an environment the more apathetic the public becomes and the easier it is to sustain combat operations, and the less edgy troops get playing policeman.
In an urban environment you'd probably rather want something wheeled, but this is good for more difficult terrain and countryside scanning. Like Afghanistan. Or Western Pakistan.