Its not a flywheel, it will have no momentum at all. Stop pushing it and it will instantly stop. The bike wheel is a poor analogy, it acts like a flywheel because it does have momentum relative to the resistance. Its no big deal and more semantics than deal breaker, but its an important distinction lest people think it has some mechanical advantage beyond that provided by the lever effect. It does not help the grinder to spin against the resistance of the burrs grinding coffee.