Interesting use of adjustment layers, Tiffany. I'll have to try your method to see exactly how it works. And I know what you mean about trying to adjust, or copy and paste, an adjustment layer instead of the image way down below. Wish I had a buck for every time I did that :).
Curves is one of the most versatile adjustments, especially in layers, that is available on Photoshop. On photos I sometimes have two or three curves layers, especially when converting a photo to monochrome (black/white). The first is to micro adjust the contrast in color (one can make more than one contrast adjustment along a curves line), then a black/white adjustment layer, then a second curves to set black and white points and modify the overall contrast if needed. And here's where the Color Selection can often help. For instance if there's a dark area where I would like a bit more contrast, I'll select that area with color selection, modify the selection if necessary, then add a curves layer to adjust only
that selection. Here's a couple examples of that last process, photos in Iceland of dark lava taken on a gray days -- talk about needing a boost in contrast.
When I use a Wacom tablet to make erasures, I use the pressure sensitive eraser brush with a hard edge. That way one can position the eraser carefully before pressing to activate the erasure.