I want to fault this but I can't. Code reviewer who's not afraid to reject code? Check. Proper testing of code changes? Check.
The process probably looks silly in this case because nothing went wrong. But with a hard-coded variable being changed, who is to say it won't break some other system by being changed? And if the variable was then moved to a config file, who's to say again that it might not break in some obscure way? Such as if the config file is not found in the uat/test environment? Additionally after all this, the manager can change the variable in the config file as they please without this process need going through again.
The process probably looks silly in this case because nothing went wrong. But with a hard-coded variable being changed, who is to say it won't break some other system by being changed? And if the variable was then moved to a config file, who's to say again that it might not break in some obscure way? Such as if the config file is not found in the uat/test environment? Additionally after all this, the manager can change the variable in the config file as they please without this process need going through again.