Yea IPFS is awesome, i have often pondered about the idea of using it for an internal family storage.
I think GlusterFS (battle-proof, but file-wise and assumes an administrator with access to everything) assumes or infinit.sh (robust ACL, but young, not open-source) better addresses those use-cases.
Also, when adding files yourself, those files become pinned by the default. Getting files won't pin automatically however. You have some more information about pinning here: https://github.com/ipfs/examples/tree/master/examples/pinnin...