Barbed wire worked well for human soldiers in WWI. It was part of a security system that also included trenches, artillery, machine guns, and active counterattacks, but it was a crucial part.

Barbed wire only slows you down.

Same with most locking mechanisms.

Oh definitely. That just makes it regular security, not security theater. (Again, assuming it's the "good" stuff from the military that you can't bypass quite so casually.)