I only “use” BTRFS as the root (and home) filesystem on my Garuda (Arch-based) desktop.
On more than one occasion, I had to resort to doing a “rollback” after borking things by playing around with packages and updates (which was my own fault). The rollback, like with a ZFS snapshot, was instantaneous.
As for the btrfs commands? I find them to be less intuitive than ZFS. (Correct me if I’m wrong, but why does a BTRFS (sub)volume need to be mounted into order to set a property?) 
I also find its flexibility (and features) lacking compared to ZFS.
The reason I even use it is because of the tenuous support of using ZFS on Linux, for the reasons stated above by @Arwen.
I also do not see any reason to use it for a NAS or pure storage solution. Sure, for a desktop or root/home filesystem on a daily driver, which I am currently using. But not as a dedicated storage server.
I suppose the dark horse to keep an eye out for is bcachefs, which could become a formidable (native) alternative option for Linux to compete against ZFS.