Integrated Persistent Storage is based around Kubernetes PVC's to integrate as closely as possible into TrueNAS SCALE. They are also heavily preconfigured to work as optimal as possible and provide options for future expansion such as NFS and Gluster options being added.
These storage options inherently are not well suited to being shared with multiple applications.
This storage is integrated into TrueNAS SCALE and completely supports reverting upgrades. Thats why this is the default (and only actually supported!) way of storing App configuration files.
Please be aware that automatically setting ownership/permissions, does mean it overrides your current CHOWN and CHMOD settings. This could break things and yes, it will destroy your system if used carelessly. It's also not wise to enable the automatic permissions on mounted shares from an external system.