It's tough to tell what motivates people to build things like these. Some areas and Cultural groups seem to latch onto certain trends more than others. There's also the considerations of where the builder was in his life, maybe he was slowing down physically but wanted to keep receiving attention at bike nights.
I think quite a few of the more brightly colored abominations would look better on the street at night, that's probably what they were built and painted for, and it'd sure rationalize the low mileage on most of them.