Do pilot disengage autopilot at DH & manually land even if ILS available? why?

why not touchdown with autopilot and then disengage it, manually throttle down, reverse throttle and put spiolers on to slow down? i hv flight simulator x.i have never been able to manually align with runway centerline in VOR e.g, st.martin island runway 09.here GPS setting is not of much help.In real life heavy planes land there...without ILS how is it possible for pilots to align with runway manually and land? kindly enligten me...