One slight advantage of a ZFS pool on an optical disk, is that it is, (in my opinion), more generic. The PAR2 or DVDisaster method requires those 2 programs to both be installed and functional. Since I use OpenZFS on all my computers, (desktop, media server, 2 x laptops and NAS), that would not be a problem, for me.
I have looked at DVDisaster, it is even loaded on my desktop right now. But, I have never used it. So it may be better or possibly more widely available, as there does seem to be versions for MS-Windows, FreeBSD and MacOS.