As far as electric assist. It depends on the person.

I've decided that if I want to do the bike thing and exposed to the weather, then I want to be pedalling, and getting the exercise. At times I've hauled VERY heavy stuff with my bike for about 10 miles.

In general I can make pretty decent time/speed with a moderate load, and go over a few short rolling hills. It is just the excessively heavy loads that send me over the top, but those are rare.

But, there are some people who may choose the electric assist for cargo, or perhaps for carrying passengers. A couple of companies either have prototypes or production models of electric assist cargo bikes.