> Replication costs have nothing to do with anything here. Replication is the cornerstone of fault-tolerance. When logic is written in high-level languages wit

> Replication costs have nothing to do with anything here. Replication is the cornerstone of fault-tolerance. When logic is written in high-level languages with some minimal good practices, most SW bugs result in crashes rather than data corruption, hence data replication plays important role in protection against bugs as well as HW problems. > Consider a bug in software used for landing SpaceX boosters... Or a bug in a trading platform. Or a bug in an automated medicine dispense I specifically mentioned: "Programmers _usually_ work with the data. <...>" In the examples you listed above software manipulates physical world rather than pure data. I thought it was too obvious to explain.