Excellent explanation.
You cannot have varying ways of discerning voter intent.
Simply counting a clearly marked ballot doesn’t leave room for interpretation.
This is where the Florida system failed, miserably.
The punchcard ballots weren't necessarily "clearly marked".
And worse: every time a ballot was handled (whether you put it through a machine, or just examine them by hand), you could knock a "chad" from the ballot -- invalidating the ballot for that particular race.
I remember a lot of people were mystified about why it was so difficult. But, the reality is that a punchcard ballot system simply has a relatively large margin of error, and it can't be guaranteed to be accurate for the scale of Florida, and the margin of victory.