If I understood the article correctly in this case the pedals are not physically connected to the wheel, it states the pedals run a generator that charges the batteries. So for this specific bike it would actually be possible to remove the belt (save for the other disadvantages of a hub motor).

This Rivian bike is bizarrely "pedal by wire" - there is no physical connection between the pedals and the rear wheel.

Instead the pedals work as a throttle to set the speed of the motor and to charge the battery while you ride, reducing depletion speed. It also harvests energy when braking.

If the battery in this bike dies completely, or is removed, you cannot pedal to move it at all. The "toothed belt" (gates drive) connects to the motor, with no link to the pedals.

In theory this design could have been done with no chain/gates drive using hub motors and still work much the same, given all the pedals are really doing is turning a dynamo-contraption to charge a battery.