ZFS boot support was just integrated (x86/x64 platform for now). It will be available in SXCE build 62.
Yes, we'll be able to boot directly from ZFS - that would definitely make life easier - no more hassle with separate partitions and their sizing, snapshots and clones for / and much easier live upgrade - those are just some examples. In b62 installer won't know about ZFS (yet) so some manual fiddling will be required to install system on ZFS.
tobb info