You're getting downvoted by cryptobros, but you are absolutely correct, there is no good use for block chain and never will be

It's a fully public database among trustless parties. To the first point, there's no reason any database can't be made public if so desired. To the second point, for the block chain to have any meaning or value beyond itself, some authority eventually needs to interpret its contents. That authority might as well hold the database or, in trustless cases, a third party trustee. Nothing about it makes sense at a very base level, you don't even need to explain the tech because it just doesn't hold up logically.