What do you mean? In all but the most extreme situations, Aperture mode using exposure compensation would seem to be more convenient and just as effective at controlling exposure.
No, it wouldn't.
http://neilvn.com/tangents/exposure-metering/exposure-compensation/
Get the exposure right once and for all in M mode. Exposure compensation levels would have to change depending on how you zoom or how you frame the shot (do I need 1EV or 1.5EV, now that I've zoomed and added more shadows to this image???).
M mode.