I'm afraid that's not even remotely true. Just two counterexamples: - MLC flash storage devices use multiple levels to store/retrieve bits [1], - Lots of contr

I'm afraid that's not even remotely true. Just two counterexamples: - MLC flash storage devices use multiple levels to store/retrieve bits [1], - Lots of control systems are implemented with analog PIDs [2]. A trivial example is a jellybean voltage regulator that computes the adjustments needed to maintain a stable output voltage independent of the load. [1] https://en.wikipedia.org/wiki/Multi-level_cell https://en.wikipedia.org/wiki/Multi-level_cell [2] https://control.com/textbook/closed-loop-control/analog-electronic-pid-controllers/ https://control.com/textbook/closed-loop-control/analog-elec...