Regarding the wall height:
The height is certainly the result of an engineering analysis. One criteria might very well be and likely is, how high can the wall be to insure that some falling from that height is not fatally injured? That is, build the wall high enough so that someone falling from a ladder of that height might be injured but not killed.
As a designer, the wall presents many interesting design problems not normally encountered
The result is not a “killer wall”
“how high can the wall be to insure that some falling from that height is not fatally injured?”
The 18 foot bollards with the anti-climb plates are roughly the high end of no-kill height. The plates defeat most climbers a few feet lower, while their feet are only about eight feet off the ground.
The 30 foot barriers will kill more than half of those who fall from near the tops.