India overtakes China to become world’s largest electric 3-wheeler market

Often the form factor is like a tiny pickup truck, so they are very versatile in terms of hauling stuff. The small size makes them very easy to park and maneuver through dense chaotic traffic. So from cost to functionality, they are in a pretty sweet spot. They aren't super safe in high speed traffic accidents, but in crowded cities, vehicles are not going super fast anyway, so the drawbacks are less important than their positive attributes.