The key element is that they are not intended as explosives; it's the "rocket exhaust" that matters. The burning gas that propels the rocket balls will quickly heat the interior of a building or a bunker to 1,000 degrees Fahrenheit, destroying the contents.
The inventor, Kevin Mahaffy, worked as an engineer at Air Force Research Laboratory's Rocket Propulsion Division, and then spent three years as the Chief of the Motor Branch overseeing solid and hybrid rocket propulsion.
The random nature of the motion makes rocket balls ideal for destroying the interior of a structure. This might be your preference when taking out a chemical or biological warfare facility. Rather than blowing it up, and spreading deadly agents over the countryside, the building interior could be destroyed.
If you think that this sounds like a "science-fictional" idea, you're right. A similar idea - called a cracker - was used in Philip E. High's 1968 sf novel The Time Mercenaries:
The "bumblebees" are alien soldiers chasing the troops. The men retreated down the tunnel in good order, strewing pill-mines and the new human-Revain "crackers" as they went. Before they had gone a hundred yards, there was a livid flash and a brittle explosion. He caught a glimpse of three bumblebees being flung backward... behind them, however, the tunnel was packed with the things. A cracker started up, bouncing from roof to floor with each detonation and leaving wide gaps in the black, tightly packed ranks.
If you think that rocket balls combine out-of-the-box thinking with solid (if futuristic) science, take a look at the Individual Air Burst gun (that works like Judge Dredd's Lawgiver) or the super-resolution vision system like Luke Skywalker's binoculars.
(This Science Fiction in the News story used with permission of Technovelgy.com)