Ctrl-Z is definitely better, since you’re catching the mistake as it happens, rather than letting it influence future lines. Working with a computer gives you a lot of tools to avoid this particular problem (for example, if you do a sketch and the lines get too thick, dim the opacity on that layer and and then use it as a vague reference for another). You can also easily hide multiple versions of the drawing and then see how they compare, afterwards.
The basic lesson still applies, which is to not get too attached to individual executions. But the computer makes it easier to apply the lesson without feeling bad about “losing” work.
Ctrl-Z is definitely better, since you’re catching the mistake as it happens, rather than letting it influence future lines. Working with a computer gives you a lot of tools to avoid this particular problem (for example, if you do a sketch and the lines get too thick, dim the opacity on that layer and and then use it as a vague reference for another). You can also easily hide multiple versions of the drawing and then see how they compare, afterwards.
The basic lesson still applies, which is to not get too attached to individual executions. But the computer makes it easier to apply the lesson without feeling bad about “losing” work.