Then you need to get our and do more real work of lots of different types. Exposed bed is often an advantage!
I have a welder, the safety instructions include "Never carry the gas tanks in an enclosed vehicle" -if there is a leak the gas tanks (nitrogen, argon, helium) can quickly displace the oxygen inside and I'll die before I know what happened.
Most things I carry don't need to be inside constantly. A little rain won't hurt anything, I wouldn't want to store anything outside but just a couple hours won't harm most things.
Also it is a lot easier to load things in a truck than a van. I can lift it over the sides (perhaps with a forklift). I can stand up in the back while arranging things - even when it is full I can stand upright.
I have used both trucks and vans to carry things over the years. Both are a compromise - and like all compromises there are negatives where something else would be better. Overall I fall on the truck is better side for what I do most often - but that is overall and I recognize there are good reasons some will choose something else.