Why? This site is obviously biased, but it presents a case for the wall saving us money: https://cis.org/Report/Cost-Border-Wall-vs-Cost-Illegal-Immi...
I'd rather spend money on dumb, long-term tech like that instead of our ridiculous military budget.
The wall was certainly a success for San Diego: https://www.youtube.com/watch?v=sxhhjfiSy2Y