Yes, you can use ZFS on memory sticks. You can also "zfs send | zfs recv" to copy a single projects dataset snapshot. You don't need to use actual disks though, if someone wants to send you project files you can have them either send you a file from "zfs send > snapshot.zfs", or send it over SSH, "ssh friend zfs send | zfs recv".

Encryption could be an issue if for example someone uses a FreeBSD based NAS for large data files, and you want to skip the network and just access them directly from your Linux box. You can "zfs export; zfs import", but not if they used encryption. That's where I think this will be useful, because then we have one standard filesystem we can use everywhere.