It's either do that, or the voter is forced to blind trust whatever system is used to record their voter intent.
To consider this problem properly, think about the problem a blind voter has with a ballot. They cannot see the record of their vote, when it's made by a mark. With a punch card, they cannot see the candidate associated with their record either.
They have to trust whoever helps them cast their vote actually does cast it correctly. There is no chain of trust between voter intent and the record of vote cast.
Now, in the context of electronic voting, a person touches a screen gives an audio input, whatever. They have to trust the system does what they intend. There is no meaningful verification due to the fact that the system could tell them anything.
When a vote is cast on media with a mark, and that mark and media are used for the final tally, the voter knows their intent was recorded, and that intent could be used directly to determine the outcome of the election.
(other corruption can happen, and is outside the scope of this comment)
Without a public vote record, voters have no idea whether they can trust the election. Blockchain does not help with this problem, unless it's a public affair, everyone sees how everyone else voted.
Banking gets around this by always having redundancies. Books are kept in many locations and all must and can be reconciled.
Voting has no such redundancy, and due to that, electronic input has a basic trust problem not being discussed enough in my opinion.