Honestly, I've never really understood the appeal of trying to shoehorn RAID into the FS itself. A more traditional softraid has always felt "good enough" to me (especially in this day and age of affordable SSDs).
ZFS in particular seems to push more toward RAIDZ, whereas I'm a bit averse to striping in general nowadays for data recovery/reliability reasons (RAID1 + JBOD is dead-simple to recover, more flexible with heterogeneous disk sizes, and much easier to reason about IMO).
Not sure where you are getting the push from to use RAIDZ over mirroring. Definitely not from ZFS proper. It's all about what's the best for the situation. Most my things are ZFS mirrors. But given a choice between RAID 3/5/6 or RAIDZ, I don't have to think long.
ZFS in particular seems to push more toward RAIDZ, whereas I'm a bit averse to striping in general nowadays for data recovery/reliability reasons (RAID1 + JBOD is dead-simple to recover, more flexible with heterogeneous disk sizes, and much easier to reason about IMO).