It's stupid because it wouldn't do anything except make the system slow, expensive, and error prone because it would be brand new untested systems.
Existing voting systems are more expensive, slow and can be cheated. Untested is outdated term check the article i provided on ehat countries and city uses this kind of voting. It's true that it still in fancy stage yet it is still developing.
Like lots of blockchain "projects" that had happened a few years ago, people blindly put the words, "blockchain" on anything because the price of Bitcoin went to a half trillion dollars and that convinced them at anything made with "this blockchain thingy" must be awesome.
Those are not connected and does not make any sense to a voting system, investments on blockchain projects are different to a blockchain system only for a single usecase - cast a vote.
But blockchain doesn't solve any problems that voting systems actually have since it makes the system inherently less secure, slower, and more expensive to create (can you imagine every vote taking 15 minutes to cast?)
I assume that this 15 mins you're talking is the confirmation time to verify a transaction. That problems can be easily solved by changing the confirmation time in the code, is it not? Change it to at least 1 minute, no need to follow what bitcoin blockchain did and having a mutiple nodes will secure it's network. I don't think it's expensive to do such thing, elections cost whereas countries have millions of $ budget in every elections that happens once in 3-6 years.
And voting is quite necessarily not anonymous, which is the very opposite of what a blockchain system does. If all votes were anonymous and not connected to an actual person but rather just a private key, then tampering and vote rigging would actually be easier than ever before.
Obviously, you don't need to be anonymous in blockchain voting system no explaination needed.