RW it also depends on the specific gate and terminal you are at. There are many places where you get pushed back and then towed a distance before you are allowed to start engines, the area between the "b" and "c" gates in Boston is one of them. You are not allowed to start the engines until you are in the throat of the ramp entrance so to speak. I'm not sure why this is, but it has been that way since I can remember......
I know that at LAX and MIA there are certain gates where you must be towed in as well as out.....so it really depends on the specific situation. There is nothing wrong with pushing back and turning out onto the taxiway in the vicinity of where you would turn to go into the gate. You may block other traffic for a moment but that is how I've seen it done in the real world.......

EHAM-YSSY B772LR
ATP, CFI, CFII & MEI, CL30, 727, 737-200, DC-9
FS9, Active Sky 6.5 w/ASG, FSPax