Problem/Justification
With every reboot you need to manually select each dataset to unlock it with passphrases via multiple clicks, which is tedious. More updates to the system, means more reboots.
A button to bulk unlock will make this process faster.
When you import an existing pool, then you do get a screen where you can enter multiple keys/passphrases at the same time (every locked dataset is listed on 1 screen).
Impact
A central button on each pool will just help with faster unlocking as the technology is already there. Impact will be minimal and only beneficial.
User Story
Reboots are more frequent with increasing updates and this button will speed up the unlocking of datasets.