My search on the net is for the military use of barriers.
Concertina wire has other purposes when it comes to politics, the media, and hopefully as a visible sign to the horde of “migrants” that we are serious about our border.
I worked at a facility surrounded by a fence topped with three strands of inward leaning razor wire.
For anyone in reasonably good shape, it wasn’t a deterrent.
They would just toss a heavy jacket or something similar over it and vamoose.