Perhaps I should clarify that by 'raw' values I meant the untransformed pixel values as stored in the .exr (or .hdr) file -- nothing to do with the RAW images produced by cameras. I just want to be able to click or hover over a pixel and have the editor show me that the pixel at (say) 4, 20 has value [1400.0, 1400.0, 701.0] instead of (or in addition to) [255, 255, 180].
Most HDR images I work with are not created by merging multiple LDR images (and for those that are, I do not have the access to the source images). In my case most of the HDR images are generated by a lighting simulation or a rendering system (some of those images contain various radiometric or photometric data rather than just 'colour'). Other images represent physical measurements of actual scenes -- individual pixels already represent the quantities I'm interested in and the input images may not exist, be inaccessible or otherwise impractical to use.
I already have tools that let me inspect such images, but they are somewhat lacking when it comes to other aspects of image editing. It's just that having that simple functionality available in a good image editor (with support for layers, channels,a nice UI and so on...) would significantly improve my workflow.
Another use case one could think of, are vector displacement maps -- a bit more general than normal maps commonly used in 3D rendering. In this case the RGB value doesn't just encode the direction of the perturbed normal but direction in which the surface gets displaced and the magnitude of that displacement (and if it's absolute displacement, you're interested in the numerical value, so you don't want for those values to be normalised).