Storage is unforgiving and you absolutely want the simplest thing to set up - for data safety.
The problem is that when you go to do recovery, maybe years after the thing was set up, it turns out the software has moved on and works differently and your storage media are in a state where at least one has failed and maybe more are dodgy, and if you have set something up with a few different interacting layers it is super easy to do the wrong thing and lose data.
I’ve lost data to “clever” storage setups before and now I stick to the “happy path” (only run the most common, well tested configurations).
I don't have that much experience with ZFS/ZoL (truly-)edge cases, but it's very reassuring that they had the right mindset when designing the tools.
Possibly, but ZoL/ZFS offers an integrated solution without any setup, etc. That's very appealing for most people.
As an admin I really don't want to have to write a big pile of scripts to do what I could trivially do with ZFS by just setting some zpool or zfs options.
EDIT: I don't know why, but people who haven't "lived" it keep underestimating just how much the convenience of "integration" means. This is not a slight, I just think that it's one of those things that you have to experience to appreciate just how much of a difference it makes.