I'm in a slightly more....redneck(?) area and the benefit to open bed trucks tends to be things more akin to landscaping, logging, wood and stone moving, and for those with hobbies; moving smaller vehicles (if they don't own a trailer attachment).

Basically the ability to throw dirty things into a hauling vehicle with good suspension on non-paved areas with easy cleaning capabilities.

It comes down to what you're doing is and what is required for a vehicle. HVAC, House work, some masonry or such you could use an enclosed vehicle for sure.

To your point, handymen and tradesmen will usually use a van or similar. And way more people own a truck than actually utilize it for the proper use cases. But there are valid reasons for open bed trucks too