Regenerative braking is not what they are talking about. The cranks on this bike are not physically connected to the wheels. Turning the cranks generates electricity which is used to power the electric motors. This is much less efficient than having the cranks physically turn the wheels.

Ebike motors are roughly 75% efficient, so we’re losing about 25% just on the output. Assuming the same number on input, this bike would produce 56% output for the energy put into it by the rider.

But yes, regenerative braking would be great. I wish my ebike had it.