I'll disagree. While it's possible to wring equal results out of a service revolver and a target gun, it's not easy. Look to those that shoot organized target events such as NRA Bullseye/Precision Pistol or any of the International/Olympic disciplines. You won't see any fixed-sight, short barreled, guns on the line. Not one.
You are absolutely correct!
For proof, compare the guns allowed, and the resultant scores, under NRA Bullseye rules and CMP Service pistol rules. The course of fire is very similar. However, under NRA rules guns can have optical sights, orthopedic grips, very light trigger jobs, etc. The CMP rules are very restricted. Sights must be "as issued" iron sights. No external modifications are allowed, etc.
CMP publishes a list of allowed pistols for their service pistol matches. Some are more akin to a "target" pistols, others not so much. In keeping with the topic of this thread, the S&W model 10 is allowed. So is the model 15, with it's adjustable sights. Lots of guys choose the 15. I've never heard of anyone choosing the 10, despite it's accuracy and other attributes.
Up until a couple decades ago, there was a Service Pistol match held in the UK in which the rules stated the only allowed guns were unmodified, as-issued bonafide service arms made on or before Armistice Day, Nov. 11, 1918. It was a difficult match, one hand firing using the ISU precision pistol target at 25 meters.
In this particular case, yes, a period-correct, fixed sight revolver as made by S&W or Colt made a fine "target" pistol.
But, going back to the OP, he does make a good point. The S&W 10, and other 38 service revolvers such as the Colt Official Police are very accurate, with close tolerances and excellent build quality. They're a pleasure to own and enjoyable to shoot.