If you live in a village and don’t have to haul much weight or drive far, sure, kei trucks make sense. I definitely saw them around Germany and France. In the US, everything is spread out. Also, kei trucks aren’t widely available in the US, and certainly not as much as Pickup trucks. Pickup trucks are also designed with use as a daily driver, since most people buying one will have that as their only vehicle. For someone with a great need of one, it’s both a highway vehicle and an off-road capable vehicle with high ground clearance. It’s a truck that will let you tow a trailer full of equipment one day and make that 50-mile commute to work the next.