Backups allow both the recovery of files deleted in error, and the recovery of a lost server. The first has a much lower impact, but is typically needed more frequently. The latter has a high impact but is rarely (hopefully never) needed.
Each of these uses place different requirements upon the backup system. In the first case, a backup system that is local to the server will give the best performance and allow a quick restore. For the second use, it may be that the building containing the server has been damaged (fire, flood, etc), and that in turn may result in the loss of any local backup server. This is Disaster Recovery, and in such cases a remote backup is essential.