I wouldn’t say worthless, certainly better than a 3-strand barb wire fence, but without some other layers like camera’s or patrols, a determined climber would bound over this without too much difficulty. Just need some rope or even a ladder.
A cutting torch would allow easy access through the unpatrolled fence.
“without some other layers like camera’s or patrols, a determined climber would... Just need some rope or even a ladder.”
With ropes and ladders, mankind has climbed Mount Everest. We can feasibly design barrier to defeat free climbers though, and also defeat the attempts of common men with common tools to go under or through the barrier. Additional obstacles on top (like barrel tops, or concertina) could make ladders and ropes more challenging as well.
The bollard barriers they are putting in now do come with all weather patrol road, cameras, sensors, and lights in the urban areas. In practice, they have found this combination very effective in reducing crossing attempts (better than 95%), and improving detection and apprehension rates among the remaining smaller flow.
The 18 foot bollards (with anti-climb plate) are harder to get over (they effectively stop women and children) - but they are even harder to get under or through.
Kids could dig away enough dirt to slide under the old landing mats in just a few minutes. With the bollards, solid concrete foundations are at least six foot deep, and you would be in plain sight while trying to dig within fifty feet of barrier.
Landing mat could be breached with crowbars, sledgehammers or battery powered tools. The bollards are heavy steel (stronger than lamp posts on Interstates), but they are also filled with high strength concrete and rebar. They are strong enough to stop a speeding dump truck attempting to ram through, and are highly blast resistant. They take longer to breach even using heavier tools/equipment, and breaches are easy to spot/hard to hide.