The autopilot is still at the control of the pilots, and usually enabled only at higher altitude. Landing/takeoff are still manually flown by pilots most of the time.

I don't have issues with a computers ability to maintain altitude, climb, or turn to a heading. I have a problem with a computer's ability to respond to the unexpected while in the air. For instance, comms failure is a scenario pilots train for and can deal with. I imagine autopilot might have some issues with that.