Oooooh! Pretty! I wonder if they can paint little M&M's or Skittles symbols on them. . ."
Taste the Rainbow, scumbag!"
It seems like a valid concept for a few reasons:
The two big sources of airborne lead on an indoor range are lead compounds in the primers, and hot gasses vaporizing metal off the base of the bullet. The big ammo makers are cranking out training ammo with lead free primers (not quite as reliable and have different ignition characteristics, but clean), and bullets that are either fully copper clad (Speer), or wrap the jacket from back to front thus enclosing the base and leaving the exposed lead at the nose (Winchester). I see no reason why specialized plastics couldn't do this job as well or better.
A training bullet doesn't need to go through anything besides paper, soda cans, milk jugs, etc... Since the price of copper has gotten to the point where it's worth a crook's time to steal wire out of abandoned houses, it makes sense to try to eliminate jackets from applications that don't specifically need them - like "condor friendly" or controlled expansion slugs. One of the reasons a lot of us got into casting is the rising cost of ammo. I theory, anyway, this stuff could knock the price of factory ammo down to something reasonable, give the environmental weenies a reason to squawk less (I'm not so optimistic as to believe they will stop), and deal with leading issues associated with mass-market loads that aren't tuned to a specific gun.