SQL Server 2005 Backups

The place I work at right now has no backups. Each server supposedly has a snap shot every 20 minutes or so and replicated to a backup SAN.

I know I need backup for easy restore, etc, etc... but I would like to hear more reasons for having .bak files instead of the SAN admin telling me he can get me the .mdf and .ldf files. Give me some fire power.

I'm also testing SQL Safe for backup compression and speed for SQL Server 2005 so any information on a tool like that would help too.