Check out this great article - written by a passionate roadie!
I wonder, is there maybe a security advantage to a cargo bike ? On-selling a stolen carbon bike might be easy, less so something boxy like these.// I was particularly struck by the writer's observation that "...cargo is the new fixie..." - more evidence that we are approaching The Singularity !
I have heard of Xtracycles being stolen, but at the 'bigger' end of the range their may be an advantage. Certainly they are harder to pick up and carry away!
If they ever become popular there will be less advantage in this regard.