Hey Mike! Sent a note in Slack, copying it here:

The reason we went with "only affect the clicked item" was to avoid forcing users to change selection just to hide a single item that's in their way.
For example:

- I have a complex selection, would require lots of manual work to re-select
- I realize there is an item in my scene that is obscuring my vision, causing visual clutter, getting in the way of picking ... whatever it is, it's a problem
- I need to Hide or make Not Pickable just that one item

That would be a very high-pain situation if you were forced to de-select, do the hide action, then re-select everything.

Secondly, the keyboard shortcut for "Hide" is available to perform the action you want, all selected items will be hidden. Default is "H", and you can choose (in Shortcut Manager) whether this action also hides children or not (default is yes).