https://www.youtube.com/watch?v=x79l7UO_qww
Caveat: The bike used is an e-bike with a powered wheel. The pedals have very little load requirements and no long-term or load testing is shown. As one of the most hardcore roadies you'll ever interact with, personally, I believe this would not last more than a week if it could survive a single ride on a traditional bike and someone like myself based on my first impression of the design. Still, the idea is impressive to me. In practice, a robust enough design will likely outweigh a chain drive by an order of magnitude. The reason the chain and cog transmission is standard is because of the balance of weight to durability. Every single gram matters on a bicycle far more than may be apparent at first.
These are basically timing belts for cars. Inside the belt are usually metal or aramid fibers that prevent any elongation of the tooth pitch. A lot of the automotive aftermarket principals of a timing chain versus a timing belt drive apply exactly the same here. The belt lasts longer and operates dry with more accuracy over time.