I only discovered ImageJ about a year ago but I’ve been working with digital images for at least 20 years. In the art/graphics/photography worlds a “curves tool” usually refers to a tool for manipulating the brightness/value of the images as a whole to have the desired effect on the histogram. It usually has nothing to do with Bezier curves, involving them is usually a disaster.
In the Unix world our main imaging tool is the GIMP, which has only an 8-bit per color data path. If you use a modern digital camera and want to work with “raw” files (direct from the camera’s sensor) those are often 14 bits per color. In the attached image most of the information is in the 0-64 range as 8-bit so it can have only 64 states when the original had more like 4000 states in that range.
I can appreciate that ImageJ isn’t intended as a tool for photographers in general but I would think such a tool would be beneficial in medical/scientific image processing. You may call it something else but I tried looking through the available plugins. In the attached image I wanted to compress the details in the highlights and emphasize the details in the shadows. Keeping as much precision as possible would be beneficial.