For me, native ZFS support is FreeBSD's killer feature. It's had containerisation (called "jails") long before Linux knew it was a thing and combining those jails with ZFS gave you several of convenience features that VMs and/or Docker offered but 10+ years ago before Docker was a thing. And yes, I know some Linux distributions support ZFS in an official capacity but having used them and FreeBSD, ZFS support on FreeBSD is easily light years ahead of Linux. It's hard to substantiate why other than saying all of those minor niggles you have with Linux+ZFS simply doesn't exist with FreeBSD+ZFS. On FreeBSD, using ZFS feels as native as using the ext4 on Linux.
It's a great shame that the industry has monopolised on Linux because FreeBSD brought, and continues to bring, a lot to the table.