Backup strategy through DO + Off-site

Hi - I have a question after reading the article about choosing an effective backup strategy.

I currently have backups enabled for my droplets. Furthermore, I configured AutoMySQLBackup on these droplets so MySQL Dumps are being captured within the file system. I am aware of the two major flaws of DO backups that currently exist: (1) you cannot download backups for the purpose of extracting specific files and (2) they are not run daily but rather every few days. It is my understanding that both of these flaws are in the process of being fixed.

It seems as if off-site backups via Rsync, Bacula, BackupPC, or Duplicity are also recommended. My question is why? The automated backups are sent to Amazon Glacier so isn’t that considered off-site? In the worst case scenario where my droplet becomes completely unusable, couldn’t I create a new droplet from a backup that was taken by DO which now resides in Amazon Glacier and then extract whatever files I needed and/or rebuild a droplet that way?

I guess I’m trying to understand the scenario where the DO backup would not be sufficient and an off-site backup via Rsync, Bacula, BackupPC, or Duplicity would be. Additionally, where are some good / cheap / secure places to store such backups?

Thanks.