"To me, hand detachable locks are one of the many small refinements that separate nicer guns from ordinary guns."

Hmmmm.
Dickson. MacNaughton. Purdey. Boss, Woodward. Etc. None have hand detachable looks and all are in the nicer than ordinary category.

Locks were made "hand detachable" for ease of cleaning & lubricating..and for maintenance. End of story.