Unlock and mount several ZFS datasets on boot with single passphrase
Why would anyone use a single passphrase for several datasets?
I generally do not endorse reusing passwords, but when setting up a ZFS filesystem for home use, it is not unheard of to use a single (secure) passphrase across several of those. That's because the reason behind splitting up pools into multiple datasets is the granular control over their properties and not the resulting fun of having to type in multiple passphrases.