So I noticed that when you create a symbol (standard or persistent) you can then create an 'On swipe left/right' action.
So my question is why isn't this also possible on all regular elements such as an image or group of images?
This feature would be useful to have.
It has been a while, so I'm not sure why that decision was made. I suspect it was the type of thing where these actions would clutter the UI and it wasn't obvious if there was enough use case for such cluttering. What is your particular use case?
Beyond just using a symbol as a workaround, you may also be able to achieve something similar using the element's On Drag to control a timeline and a little bit of code to see if it passed specific thresholds.
We do have an item on our tracker with this request already though; I've added your feedback as a +1 for it.
I guess it makes sense in my case (creating a slider) to have this functionality on a symbol which will be present across all scenes.