Studio1337 offers daily offsite backup services to all of its shared and reseller hosting customers. We offer this as an opt-in service because many Webmasters prefer to rely on their own offline backups as protection against server failure. Rather than build this cost into every plan regardless of whether every customer needs it, we've made this an affordable, optional service.
Regardless of whether you use NAS or not, you are ultimately responsible for the integrity of your data, and we strongly encourage you to keep updated files of your own too. NAS will decrease data loss risks significantly, but no system is 100% foolproof!