Imagine a generator on a bicycle, you pedal to make a light bulb light up. There is of course inherent friction in the system, but a large fraction is actually pushing magnet fields around to produce electricity. That part actually has no friction, while it's not 100% efficient in the form of stray magnetic fields and some heating, normal metal on metal friction is a very small fraction.
Normal brakes use 100% friction, which of course causes substantial heat, and increases wear and tear on the pads, the rotor, and brake fluid. These type issues are why it's often recommended to use a lower gear down hills so you can offload the brakes with engine friction.
So not only does regenerative braking produce less dust, but it produces less heat, and the brakes/rotors/fluid are on average cooler and in a state where any needed braking causes less wear.
