Filesystem in Userspace (FUSE), cloud storage is an open source FUSE adoption functionality provided by GCS. It allows users to access and operate GCS buckets from their Linux or OS X machines. It translates object storage names into a file and directory system and interprets the / character in object names as a directory separator.
Thus, objects with the same common prefix are treated as files in the same directory. Applications can interact with objects like files in filesystems. We now no longer need to recode our shell scripts to work with gustil commands and gs://... paths. This can be a significant win if our shell scripts are too complex or too important to rewrite. But on the other hand the filesystems mounted via gcsfuse are much slower than persistent disks.
Cloud storage FUSE itself is free. But charges for bucket storage...