Lighter weight than 4 wheeled car, partly due to MC vs. car safety and emission standards.
Potentially very high performance. Can drift in corners with nearly the power/weight ratio of a 2W motorcycle.
As well as lower barrier to entry for a manufacturer, most places allow “home made” motorcycles to legally take to the road, so these can be built as garage projects. The Chromed example from the OP is based on a VW rear end, for example.
Low slung trikes can be quite stable, especially the tadpole configuration. (two front, one back wheel). Taller trikes may not be able to take corners nearly as fast as a two wheeled motorcycle. Think Tim Conway tipping over on a child’s tricycle. They are stable when stopped, in parking lots, etc. which is where some people struggle to keep a two wheeler greasy side down.
One downside is that one wheel runs in the grease stripe in the middle of the traffic lane. This can be a real concern on wet roads, especially when it just starts raining. There can be more debris there leading to more flats as well. Sidecar motorcycle rigs avoid this via asymmetry, which also provides radically asymmetric steering response.