Some compression stats from my local setup. I work with a lot of source code (Android / AOSP), and big output directories (hundreds of gigabytes)

ZFS compressratio: source: 1.40x (Separate pool) output: 1.68x-2.49x (Multiple datasets to make management easier)

The output compression allowed me to use a 1TB drive as a 2TB drive effectively, allowing me to store a lot more output and not have to wipe away build output from x to build y.

That alone makes zfs worth it for me (and I know many other Android devs who use it in a similar fashion)