Should my AC empty condensor water to the roof?

My a/c's condensate usually drips off the gutter extender outside the driver's side window after it leaves the roof. Doesn't hurt anything. That is a way better design on most lower cost units than having any water pipe running unnecessarily inside a thin wall panel.
I have found some green slime to the rear of each A/c unit as this area rarely sees direct sun during storage. It is easy to clean-up or just let the heat dry and evaporate it.