I favor cloud storage here since you can configure write-only storage pools (without delete, or at least with versioning). Whereas "offline" backups must come online for new copies, and that's a window for infection of the hosting file system, barring well-configured snapshots or the like. Also it can be your second location for the "three copies, two locations" rule of thumb, especially if you are an SMB with only one physical space.
(The opposite plays here, too. If everything you have is in the cloud, you should keep local backups.)
(The opposite plays here, too. If everything you have is in the cloud, you should keep local backups.)