Most people who carry J-Frames do not carry a speed loader, maybe speed strips, but either way the reload probably won't be that fast, and you have 5 rounds of 38's, vs 5 or six rounds of 45's to to get the job done.
If you want to talk speed of shooting, I shot a bowling pin match one time with a Ruger Super Blackhawk 44 mag and had one of the fastest times of the day, shooting against 1911's and various doubleaction revolvers. Of course the trick was not to miss, so I didn't need a reload and the 44mag always cleared the pins from the table.
So to tell you the truth, I would not feel like I was at much of a disavantage with a large caliber singleaction against a Wonder 9, under most realistic confrontations I can dream up, while carrying CCW
What do I really carry? It just depends, could be a Colt Mustang Pocket lite, or Glock 26, to a Lightweight Commander 1911, but I have also carried on occasion a Colt 45 singleaction replica, or a Ruger Singleaction, but the singleaction is a thinking man's gun, and spraying and praying is not an option, but if the chips were to really fall, I would at least choose to have with me at the time, a Singleaction 45 or 44, vs a mouse gun or a J-frame, and that's not because I can't shoot my mouseguns or j-frames accurately because I can.