Sidelocks can sure be pretty, even though they are more vulnerable to stock damage or failure. I've owned a few.
But their primary advantage over a boxlock are the sets where spare locks are included with the gun, so one or both can be changed out after parts fail afield. Perhaps a secondary advantage is being able to pull the locks to dry them after a dunking in the duck marsh (or an oversized gin-and-tonic, perhaps more likely these days).
When is the last time anyone saw fitted spare locks offered with a sidelock?
