The controller isn't stateful; it's just an interface to the disks. If the controller fails, but the disks haven't, then all you've lost is the time it takes to plug the disks into a new controller.
With RAID1, there's also nothing specific to the RAID configuration inherent in the way the data is encoded on the disk. You might have to carefully replicate your configuration to access the filesystem from a failed RAID0 array, but you can just pull and individual disk out of a RAID1 array and use it normally as a standalone disk.
You will have a better chance at uptime with a RAID than a single drive so you hopefully don't have to climb up ventilation ducts, walk across broken glass, and kill anyone sent to stop you on your quest to reconnect those cables that were cut.
