The article's two main points are:

1 - a ban won't work
2 - properly programmed autonomous weapon (AW) could reduce causalties

So, the conclusion goes, we should totally dig AW.

Point n° 2 is the most fragile: they could very well reduce as increment causalties, depending on how they are programmed. It's also true that the availability of cheaper soldiers might make for cheaper (i.e., more affordable) wars. But point n° 1 is debatable also: after all, the ban on chemical and biological weapon has worked, sorta.