Hmmmm
"although its curious as to why they dont just make robot versions of the cockroaches."
- Yes, I agree!
"We decided to use biobotic cockroaches in place of robots, as designing robots at that scale is very challenging"
- Nanotechnology has been around for a long time and there is plenty of innovation in miniaturised robotics if someone cares to look for it. I dare say the financial cost of researching and implementing the cockroach solution is at least, if not more, expensive as using robotics to achieve the same thing.
Bad day for science.