All my current CCW sidearms have BGBGBH (see * below) adjustable sights; y\'all probably consider them \"fixed\" sights. Less moving parts, less snag-prone, all the usual reasons. At civilian defensive handgun range, they\'re adequate. I can keep all rounds from my M642 on paper at 25 yards, standing unsupported; same for my Kimber Ultra CDP at 50 yards. My NAA Black Widow? Well, 15 yards, but it\'s a \"when I CAN\'T carry another sidearm\" option, and I consider it a whole lot better than nothing!
When I was in law enforcement, working plainclothes & felony stakeout assignments (late 70s & early 80s), I felt obliged to do better for my constituents. At the top o'the heap in those days was the S&W M19, which had adjustable sights. With my 4\" model, sighted for my favorite load (Remington 125 gr. JHPs), I could reliably keep my hits in the scoring rings of a B27 silhouette at 100 yards, from any braced position.
As a \"mere civilian,\" I have no expectation of engaging an assailant at that range in self defense. I know, I know; anything is possible, but still . . .
* \"By Guess, By Gosh, and By Hammer\"