It comes down to ease of use vs control.

If you want it easy, obviously, its easier to drive an automatic....it shifts for you.

If you want control, well, maybe the automatic doesn't shift when YOU want it to, or have the ratio you want...so you need to take control and do it your self.

There are some advantages on or off road for both, like the torque converter taking up some drive train slack and the manual's clutch burning up if you need to go too slowly for your gearing, etc...

vs the ability to engine brake on down hills and to choose a gearing set more suited for a situation, etc.

Generally, the manual will out accelerate the auto, and have more control/finese....

and generally, the auto will simply mean one pedal to go, and one to stop...leaving your attention to other details more free...like that Big Mac, etc.

So there's no wrong answer - its just a question of priorities, convenience vs control....you pick what works for you.