I think the argument for a wall is that it will stay in place and not require repairs - that won’t be made - by future administrations. Notice that even Ryan and Flake are ok with “fencing”. If you want something that works, you follow Israels lead and build a wall
Here’s the reality. The establishment republicans will never allow a big beautiful wall. Its not happening folks. I want it, you want it we all want it but fencing done right is cheaper and faster.
Even better since the crimulous bill is a suggestion on spending and not a budget Trump could easily dip into some of those DOD funds and instruct the corps of engineers to start throwing up a two fence system on pertinent sections of the border. With the corps of engineers doing the job its now a military project totally within the purview of the President. He can bypass Congress and give Ryan and McConnell the finger.