The reason I want blockchain for my voting system is the same reason I don't want it for my currency.

It's too secure. It's permanently auditable. If we had blockchain a century ago we could trace back everything a presidential candidate had ever bought. All we'd need us his current wallet identified and we could follow backwards through every transaction.

This is excellent for votes, which is why they won't use it.

This is orwellian for money, which is why they will.