What is a velomobile
Essentially, a velomobile is a completely street legal bicycle (or rather tricycle). Electrical assist is an option though.
Weather protection and luggage space
The body of the velomobile is not only aerodynamic, but it also protects against the weather - cold, wet and also sun! It provides easy storing space for your luggage.
Fast and comfortable
Because of the aerodynamics you have a better effort to speed ratio. You can use this both ways, go faster at the same effort, or spend less effort for the same speed. Many times it will be in between, ride with a little less effort and more speed at the same time. Not only the effort to speed ratio helps, also the comfortable recumbent riding position ensures that only your legs feel the effort while everything else is relaxed.
Anyway, it's easy to cover greater distances. A commute of 15-30km (10-20mi) is easy, but up to 40-50km (25-30mi) is no exception.