When you have a complex layout, and want to have a slice containing, for example, one picture in it, you want to draw a slice around it and snap it precisely. |
It would be very difficult to use transform panel for that.
Also, I know that it is possible select the object and create a slice from it in export persona. But this method creates a layer-dependent slice, which does not allow including objects outside hierarchy branch. Then I cannot have, for example, a separate layer for all picture frames and later switch it off to batch export pictures for printing, when you need no frames.
(pictures and frames is just a simplified example, not an actual problem)
Simple snapping for layer-independent slices would easily solve all of this.