Except in the analog world its not so clear, you can't just say +3V=1. What if its 3.7V? or 4.5V? Early tools weren't that accurate either so you needed more range to deal with it.
It should be stated as ranges for clarity. It’s never an absolute voltage (quantum mechanics itself won’t round that nicely). Although this is also true of binary. >x volts = 1 otherwise 0 volt n binary. Same thing in ternary just with 3 ranges.
Yeah at some point you have to deal with the transition between the clean conceptual world of digit computing and deal with the fact a circuit can't instantly transition between 0v and 3.3v/5v/whatever level your signal operates at.
