KORG Pa models. What the difference between SAVE ALL and FULL RESOURCE BACKUP ?.
What is each doing differently ?.

When you do a save all rather than restoring the whole keyboard, you can reload whole banks or individual files. Ie if you edit a user style and you want to go back to just that user style you can reload the individual style.

MusicalMemories. Understood.

Think of the Korg filing system is like looking at a slide through a microscope first the xxx.set is looking with the least magnification as you zoom in more you look at the contents of the xxx.set In more detail.