The .38spl +P out of the 4" test barrel is 950 fps.
The same bullet out of a 4" test barrel in .357 mag is 1450 fps.
All that really matters in my mind is whether or not the bullet moving at 850 to 950 FPS (to account for short range--perhaps out to 50 feet) has the proper terminal ballistics characteristics to stop an attack effectively. I think it does.
People have a tendency to want "the best" that leads to needless optimization. The better method is to design requirements for the solution to a problem, or problem set, and determine the range of fit. The snub nosed revolver is intended for fast handling in short range encounters. I believe the 38 Special load has enough power and accuracy to stop attacks.
I load my Ruger Alaskan in 44 Magnum with the previously mentioned Speer Gold Dot Short Barrel ammunition. It is intended for defensive use against humans. It is likely inadequate for black bear, which is the largest critter I could encounter in my area. I change the ammo to moderate soft point hunting loads when I hike. I still carry a small revolver in 38 Special +P loaded with JHP in my pocket. Both guns meet my self-defense requirements when loaded appropriately.