The main reason I think this normally isn't done is that it requires downtime to do safely most of the time. In order to not lose data, you can't have any writ

The main reason I think this normally isn't done is that it requires downtime to do safely most of the time. In order to not lose data, you can't have any writes between the time when the backup was taken and the present, or you need code which reconciles additional state and adds it onto the backup before switching over. Normally, backup restoration is done during a maintenance window where the site is disabled so no writes can happen, and then usually a window of writes are lost anyway (i.e. 'last X hours, since the backup was taken') For your use-case, do you just have very few writes? Do you lose writes? Do you have some other clever strategy to deal with it?