Bold added by me.
Not by the time the conversion is done. Then you have a fully analog signal. (Once the bandwidth limit is applied to the output, the steps are gone.)
But of course you’re missing the real point: it’s about how you interpret the signal on the input.
The following example, is NOT how I think things should be interpreted. But some other(s), but I won't mention names, **might** think that way.
Example:
A 5 volt (output is precisely 0 volts for logic '0' and precisely 5 volts for logic '1'), all digital logic series, which treats input (threshold) voltages below 2.5 volts as logic '0', and equal to or above 2.5 volts as logic '1'. Hysteresis, noise thresholds and other practical real life phenomenon, are being disregarded, for this example.
Therefore, it is a 100% analogue device, a non-inverting buffer, is actually a 1 bit, A to D converter. Which is equivalent (internal circuitry wise) to the inverting input being connected to exactly 2.5 volts, and the non-inverting input, being used as the input.
Much like a
comparator, sorry, I mean op-amp, as this is 100% analogue.
In other words. Yes, a non-binary input/output digital system, **could** be interpreted as being equivalent to an A to D (and DAC, depending on if input or output, etc) converter. But would still be a 'Digital System', just with more than 2 states, but still a fixed number of defined output (voltage, current, etc) levels.
In the same way a simple wire (or bunch of them, possibly screened or similar), can be used for many different purposes, which would tend to change its name. E.g. Wire, Cable, Accelerator-Cable, Tie-Wrap, USB lead, Meter Leads, Lighting Cable, Breadboard Leads, Ethernet Patch Cable, etc.