Part of the thesis of Datomic (and also Crux, as I understand it) is that cycles and storage have gotten so cheap that some of the design assumptions made by tr

Part of the thesis of Datomic (and also Crux, as I understand it) is that cycles and storage have gotten so cheap that some of the design assumptions made by traditional databases no longer necessarily make sense for large segments of the application software market. One of the major ones being challenged is that storage is so expensive that your updates to the DB need to be destructive. That's still true for some domains, but for many, many domains, e.g. ones where historical reporting is important and write volume isn't terribly high, it'd be much better to have an immutable database (facilitating historical queries), even if it means paying a little more in hosting costs, than to build the necessary features on top of a destructive database.