I filed #11294, it's a non-issue for me now. Seemed like an API change stability issue, which happens. I think what a crypto-user might care about more in ZFS vs LUKS is precisely what gets encrypted: LUKS can be the entire disk, whereas ZFS is going to need some metadata to know what is there, which keys unlock it, etc on at least a per-dataset basis. It's not a tradeoff that affects my particular threat model, but it's worth understanding as a crypto user.