Robert Capa once said, "If your pictures aren't good enough, you aren't close enough." Though he was a great street photographer, I believe he was talking about his photos of war, but I think it still fits.......of course the compactness of the GR III helps, a lot!
I shoot in RAW and High quality JPG set to BW. I use the BW jpgs as a contacts / proofs to see which images work the best in BW.
Then all RAW images are imported into Lightroom. edit out all the bad shots, miss focuses, blurs, etc... and delete them as well as any other shots that don't work, if they don't work today they won't get better with time, so they get deleted too.
next basic darkroom adjustments in Lightroom. exposure, sharpening, etc.
then if the shot works in color it's done. If I'm changing it to black and white, it gets opened in Silver Efx pro and adjusted accordingly.
the black and white jpgs right out of the camera are quite good, but I like the editing capabilities of RAW. simply desaturating the image doesn't get the look that I like or one that even compares to the native BW jpgs out of the camera, which is why I use Silver efx for that.