Check out https://www.phoronix.com/review/linux-617-filesystems/5 "Geometric Mean of all test results". You will find that OpenZFS is ~35% slower than btrfs.
I love ZFS but I am aware about the performance it delivers.
When I use firefox, sqlite performance matter more than any random benchmark. The same benchmark shows sqlite is 3x faster on zfs.
A good benchmark suite consists of good benchmarks chosen carefully. These benchmarks are not chosen randomly. They represent diverse ways to "stress" or exercise the system. Real life workloads are indeed closer to "Geometric Mean" of various benchmarks by definition because real life workloads are diverse. Not everything would be like sqlite3 which is single pattern of file system usage.
Geekbench, Cinebench, 3DMark etc. are all averages or geometric means of various benchmarks also.
> When I use firefox, sqlite performance matter more than any random benchmark.
You've selected a single benchmark (sqlite) and said it's so important to you that it overrides everything else when you are comparing ZFS vs btrfs.
If you feel that a single benchmark like sqlite is good enough then that is fine -- your decision. I am hesitant to do the same and prefer geometric mean.
And only than those benchmarks would be more interesting to me.
Secondly: are you aware that ZFS includes what LVM does on Linux, and so you don't need a separate tool for it? This makes the comparison tricky but it's important to consider.