"Fancy setup but too busy. Why aftercool and dryer?"
Depends how dry/oil free you need the air. With the present cooler Hap has, it will suffice for most purposes. On very humid days even with a good cooler the air at ambient temp from the coil cooler still has moisture; when spray painting the remaining moisture might present a problem, not a bad idea to have a drier... not fun to shoot enamel/oil base and have a drop of water ( oil contaminated) from the gun, or shoot lacquer with varying amounts of moisture in the air depending on the weather (inconsistent spraying, due to varying thinner amount/type to compensate for the moisture) .