Just got my new C8 today and moving things over... I noticed to recall a scene in Button Controller App, I had to choose "Adjust Shades, Blinds, Fans" for the action? No biggie I obviously found it eventually but seems an odd place?
That category was once labeled with scenes, then the label was removed (as well as the action for new rules, though existing selections remained for already-created rules or button rules) when Groups and Scenes was deprecated in favor of Room Lighting. While Groups and Scenes was brought back (for new users; again, this did not affect existing uses), the category in Rule Machine (and Button Rule, which shares substantial code with the former) has remained named the same ever since, even though this action was one re-added.
That's the history, at least. 
The List of Actions section in the Rule Machine docs have a list of what actions you can find under what categories, and these are nearly the same as what you'll find in Button Controller. So, that's one way you may find helpful to find things without digging through everything.
As for the implicit request, I've seen a couple other people get confused about the same thing, but I'm not sure if there are any plans to add this phrasing back or if it's intentional. Use of Room Lighting over other options still seems to be encouraged. So, I can't speak to this in particular.
