To be fair, there are places along the border where agents prefer a technological barrier coupled with strong fence barriers to an actual wall. There are also long stretches where a genuine wall (also with tech support) is a better barrier. So the entire border is not a one size fits all...and I have no doubt that all of this will factor in to the actual construction. "Wall" in this context does not equate to something like the Great Wall in China...but neither is it just a big fence. What it will be is something in between and it will vary according to terrain and other tactical factors.
True enough. With varying substrate, terrain, and need for water access, the solution to the problem will vary. For a significant portion of the border, a physical wall will work, but even that will have to have some sort of surveillance and a rapid reaction force in case the coyotes or cartels breach it. In other areas the solution will be a different barrier or other technology, but the whole idea is to either close the border to crossing, or to channel the illegal border violators into terrain where they can be more easily captured. If thy want to fight, such terrain will be tactically advantageous to our people, not theirs.