Append-only/log-structured databases are worthwhile (SQL databases end up similarly structured internally). "Mining" and all the overhead it entails is only worthwhile if you need zero-trust, and few if any use cases do.
Consensus shifts that trust from authority figures to others in your group. Bottom-up trust instead of top-down.
When Governments falsify data, in my opinion bottom-up consensus doesn't help, since governments then also could simply participate in that consensus-forming process (see 51% attack)