My city (Karlsruhe) actually gives subsidies to anyone buying a cargo bike. Mostly they are used to transport kids. I, however, have to go up and down a stair to get my bike out (typically Gründerzeit house) . Further than that they are totally impractical if the one bringing your kid to kindergarten isn't the one picking it up. They are also difficult to park anywhere. However, to me this is the green version of the SUV . Makes not much sense but keeps your middle class happy... I guess there are worse trends