This is an excellent question! Here are a few of the benefits of using DreamObjects to store your data, whether for your site or backup:
Redundancy - We keep 3 copies of your data in our self-healing storage cluster. Data integrity is constantly monitored and any corruption found automatically triggers rebuilding that data.
Durability - In addition to keeping multiple copies of your data, we also place it strategically in the cluster so that it's fault tolerant. The same data is distributed throughout the cluster so that a failure of a disk, rack, or entire row in our data center will ensure your data is safe.
Speed - High performance read/write access through commonly used APIs. Access to DreamObjects also goes through a load balancer ensuring availability. We're currently testing various CDN options and will be providing this option as well.
Scalability - You'll never worry about running out of space again. Very simply put, it's just one less thing to worry about.
So those are the big benefits, but let me address your questions more directly. Offloading content from your web server to DreamObjects can help with performance. As for backups, DreamObjects is much more redundant and durable than the included backup offering.
I hope that brings a little clarity into why we're offering DreamObjects.