They don't state what chain system they're comparing it to. Given the coverage in the article, their base case may be a three+ wheeled cargo bike with a long /

They don't state what chain system they're comparing it to. Given the coverage in the article, their base case may be a three+ wheeled cargo bike with a long / complex chain run. In those cases, a complex chain run results in significant energy loss compared to a regular two-wheeled bicycle. Back when I bicycled, I first noticed this when I added recumbent bicycles / tricycles to my "fleet". The two wheeled recumbent had a long chain and guide wheels. The three wheeled recumbent had a long chain, guide wheels, and guide tubes.