As I've pointed out before (link), jihad attacks have indirect consequences that are far more profound than the damage and death caused in the original incident. In any rational assessment of the pros and cons of Muslim immigration, the likelihood (approaching certainty) of jihad attacks and both the direct and indirect consequences of those jihad attacks would have to be factored in.
...the city region of Brussels is experiencing its worst crisis in the post-war era as a result of the attacks of 22 March. This capital of slightly more than a million inhabitants could see 10,000 jobs disappear soon, according to the city's chamber of commerce and industry. Thirty-one thousand people, living in Brussels or in the adjacent areas, have already been temporarily laid off. The drop in business turnover varies between -20% and -40%.Source
So the next time you hear a politician extol the economic benefits of Muslim immigration, remind him of this.