I sometimes work with a lot of layers that I would like to group together into a
folder. Then I could perform operations on that folder as if it were a layer
itself: e.g. merge layers (inside folder), merge down (all layers in folder
merge with layer beneath it), show/hide (all layers inside folder), and so on.

Obviously, one would still want to be able to open that folder and continue
working on the layers inside as normal.

Thanks for all the hard work,

david