The movement doesn't have figures for how many converts this part of its mission has produced. And it's emphasised that it's an addition rather than a departure from the door-to-door evangelism, but adherents are optimistic that the new tactic is making an impact.
I like this quote from the article because it shows what the carts are really about. JWs get discouraged by the door to door ministry because nobody is ever home and they spend hours doing nothing. Now they still do nothing, but at least they're around people, there's a buzz around them, and they can always reason that merely by being seen they are witnessing. They also have to be approved to do this particular work, so they feel special. It is busy work aimed at keeping the illusion alive that they're really helping people. We all know that statistically they bring in few outsiders and most growth is from within. They don't want real numbers on things that matter, like converts from their work, they only want numbers based on activity (hours, placements, etc.). It's all for show.