In less than a month I've had more non cyclists ask questions and show genuine interest in my E-cargo bike than I have had for my regular bikes in the past 5 years.
A couple of guys at work who never showed the slightest interest in my regular bikes were peppering me with questions like where I got it, how much was it, do they allow test rides, ECT.
I don't think we'll see an explosion in their use like Asia and Europe, but I suspect they will continue to gain popularity with those outside the cycling community.