Why in the world aren't you shooting RAW?
If you are asking me (which I know you were probably not!) I would answer that I am an amateur, as in doing it for enjoyment, not out of necessity of paying the bills or meeting anyone else's quality standards, so I can afford to choose my trade-offs of convenience against image quality, and I do not enjoy spending a lot of extra time processing each RAW image.
I imagine that even a professional who takes a lot of photos might prefer avoiding a significant amount of unnecesary extra "non- picture taking, non- eating and seeing the family" time, if and when in-camera JPEG conversion can give good enough results. If absolute best available image quality were always needed, few professionals would ever have stooped to using 35mm film.
So to me, the question is if and when the best JPEG is close enough to RAW in quality, and this seems to vary greatly between cameras. The E-1 that I use has an unusually low compression ratio of about 2.8:1 in its best ("SHQ") JPEG option, and perhaps because of this, the few RAW vs SHQ JPEG comparisons I have made with it show no differences. But that might hold only for "normal scenes" where sharpness and color accuracy are the main issues, not high contrast scenes (sorry, "scenes of high subject brightness range"). Hence my curiosity.