ABP is not intended for all KeePass uses. For some purposes, such as those described on this page, ABP is ineffective, dangerous, or simply unsuitable.
Backup To Same Hard Disk: If your KeePass environment comprises a single PC with a single hard disk, then backing up your database from one folder of the disk to another will be of limited value. Recovery from the backup copy will be possible only if a partial disk failure caused the original database – but not the backup copy – to become unreadable. If the hard disk crashes, the PC malfunctions, the PC is lost or stolen, or the building containing the PC burns down, both copies would be lost together. Note that a single hard disk partitioned into two or more drive letters is still a single hard disk. No backup application – ABP or otherwise – will protect your passwords from most perils in this situation.
Synchronized Copies: A user may want to have n different copies of “the same” KeePass database distributed on USB flash drives, a network, and/or even the Internet. The intent is to open any of the copies as an “original”, and to have the other copies automatically updated (“synchronized”) by ABP as the state of the open copy changes. It is dangerous to use ABP for this purpose. Here's why: Suppose ABP is unable to “back up” to a particular copy of the database at a particular time. It is to be expected that this will sometimes happen; otherwise, why have more than one copy in the first place? When this un-updated copy is later opened by KeePass as an “original”, the ABP “backups” (now all successful) will clobber every copy of the new database with the old one. And this will happen even if the user does not explicitly save the out-of-date copy. [The existence of so many quoted phrases in this paragraph illustrates that ABP is being enlisted to do a job for which it was not designed.]
Checkpointing: ABP is not designed – nor is it especially suitable – for checkpointing. See Backup versus Checkpoint for a detailed discussion of the differences between the two.