Curvemeister does provide soft-proofing, Mark. (You do love soft-proofing, don't you )
Several things stand out for me in this program. One of them being you can see and adjust all channels of your curve in one window. Another is that you can switch to any other mode (RGB, wgCMYK,Lab,HSB) to work in without leaving your image preview; you get a new curve with all channels showing.
But the thing I am really intrigued with is the masks in this version: you can see masks made from all channels from the modes I listed above (except C,M,and Y) in one window, and select one to use while working on your curve. You can be working in Lab, for example while using a mask from a 'K' channel. In color, this is great because you can pick a channel to enhance an area of color to suit, but this can also work for B&W images.
If you change your profile to Gray Gamma 2.2 in PS, the soft-proofing allows you to see your image in B/W, in all different color spaces, and use any of the channels in those spaces as masks. You are not losing your channels, as you are in PS grayscale, and you are not working on color selections as you are in PS's Hue/Sat, and (if I understand correctly) ACR/LR's HSB sliders. Or PS's B/W sliders. You are working on channels , and you are able to see them in the preview. Very cool!
Spoonfeeding? I think the creator has tried to make the program accessible to beginners, but like much software, your results will be in keeping with your creative and inquisitive efforts. There are definitely some features that Photoshop doesn't have, that are integral to adjusting an image using curves.