Unfortunately, walls do work, whether to keep people in or keep people out, they do work. Walls are characterised by three aspects. One, who makes them, where is it built and what is the point of the wall? The last item relates to whether you want to keep people in or out (or both...).
This this case, it is to keep the Palestinians out of Egypt, unfortunately, the same as that of the Israeli's. And dont forget, the Sinai can be termed as disputed land as well. I have yet to find a good consistent reason why that line on the sand between Gaza and Egypt is there. The consistency has to lie between all the boundaries around Israel and when? But I am drifting from the point.
Again, this wall will work and keep people out. For people who point to the smuggling aspect going on, yes, so was the same with the Berlin Wall. Generally it is not possible to prove a negative but in the case of the Berlin Wall, you can with a greater sense of confidence. You saw the difference even with the same regime on the East German side when the wall came down. So yes, these walls do make a difference. Also see my other general essay on walls as well as how another country, Pakistan, is being fenced in.