For movies/pictures and sound (well everything that is already compressed) you can deactivate it, zle too.

EDIT: On the other hand leave it on, zfs tests the file if it's compress-able..if not it makes nothing:

https://klarasystems.com/articles/openzfs1-understanding-tra...

>>ZFS Compression, Incompressible Data and Performance

>>You may be tempted to set “compression=off” on datasets which primarily have incompressible data on them, such as folders full of video or audio files. We generally recommend against this – for one thing, ZFS is smart enough not to keep trying to compress incompressible data, and to never store data compressed, if doing so wouldn’t save any on-disk blocks.