It would be very useful to be able to group columns so that we can hide groups of columns rather than hide selection but only unhide all.
This would ease readability of large spreadsheets by allowing users to quickly show or hide columns that they are interested in.
We really need this function as well. We use our sheets for project management and we have columns that affect different teams. I'd like to be able to group it somehow either by identifying it with a color or using column header grouping.