This is, I admit, not really an accurate comparasion but the Civil Air Patrol in America uses mostly 'amateurs' and is a now a huge organisation that helps with everything from obversation of drug running and illegal immigrants to shifting aid to natural disasters. I think the danger of situational awareness loss and the other risks like 'poor GA image' are rather remote and sound more like eye ball rolling and even dare I say it anti-microlight feeling on the part of posters.
OK in reality maybe they won't be much use...but I don't see why people seem to have a problem with them.