Basically self-explanatory. Mikrotik's RouterOS has two distinct functions, one which backs up the router and one which exports the configuration of the router. What exactly is the difference, and when should one use one instead of the other?
Reading the actual vendor documentation is usually the best approach to answer such questions.
The configuration backup can be used for backing up MikroTik RouterOS configuration to a binary file, which can be stored on the router or downloaded from it using FTP for future use. The configuration restore can be used for restoring the router's configuration, exactly as it was at the backup creation moment, from a backup file. The restoration procedure assumes the configuration is restored on the same router, where the backup file was originally created, so it will create partially broken configuration if the hardware has been changed.
The configuration export can be used for dumping out complete or partial MikroTik RouterOS configuration to the console screen or to a text (script) file, which can be downloaded from the router using FTP protocol. The configuration dumped is actually a batch of commands that add (without removing the existing configuration) the selected configuration to a router. The configuration import facility executes a batch of console commands from a script file.
Dont use backups, except if you want to keep the passwords in the backup file. Config export is more portable (i.e. you can push the config to another device, and even another type of device, given it has more or equal capabilities).
Standard case is : you device is broken, so you put another one (similar) and load up the backup.. which does not work because it's another device. You are screwed. Don't use backups.
Reading the actual vendor documentation is usually the best approach to answer such questions.
http://wiki.mikrotik.com/wiki/Manual:Configuration_Management
Dont use backups, except if you want to keep the passwords in the backup file. Config export is more portable (i.e. you can push the config to another device, and even another type of device, given it has more or equal capabilities).
Standard case is : you device is broken, so you put another one (similar) and load up the backup.. which does not work because it's another device. You are screwed. Don't use backups.